cachefiles: Fix NULL pointer dereference in object->file

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/cachefiles/interface.c",
                        "fs/cachefiles/ondemand.c"
                    ],
                    "versions": [
                        {
                            "version": "c8383054506c77b814489c09877b5db83fd4abf2",
                            "lessThan": "d6bba3ece960129a553d4b16f1b00c884dc0993a",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "c8383054506c77b814489c09877b5db83fd4abf2",
                            "lessThan": "785408bbafcfa24c9fc5b251f03fd0780ce182bd",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "c8383054506c77b814489c09877b5db83fd4abf2",
                            "lessThan": "f98770440c9bc468e2fd878212ec9526dbe08293",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "c8383054506c77b814489c09877b5db83fd4abf2",
                            "lessThan": "9582c7664103c9043e80a78f5c382aa6bdd67418",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "c8383054506c77b814489c09877b5db83fd4abf2",
                            "lessThan": "31ad74b20227ce6b40910ff78b1c604e42975cf1",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                }

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/cachefiles/interface.c",
                        "fs/cachefiles/ondemand.c"
                    ],
                    "versions": [
                        {
                            "version": "5.19",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.19",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.129",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.78",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.11.11",
                            "lessThanOrEqual": "6.11.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.2",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.13",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }