octeontx2-af: fix cn20k mailbox lifetime on repeated rvu_mbox_init()

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "drivers/net/ethernet/marvell/octeontx2/af/cn20k/api.h",
                        "drivers/net/ethernet/marvell/octeontx2/af/cn20k/mbox_init.c",
                        "drivers/net/ethernet/marvell/octeontx2/af/rvu.c"
                    ],
                    "versions": [
                        {
                            "version": "e53ee4acb220acab6832669334279367b0206af6",
                            "lessThan": "c08314f91782983d67af0807ed1360e404ac4a8b",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "e53ee4acb220acab6832669334279367b0206af6",
                            "lessThan": "a0fcbea79f034f49bdd44915f28938922023458d",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "e53ee4acb220acab6832669334279367b0206af6",
                            "lessThan": "3b11a77f69980932c3924054d66e565c9a135747",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                }

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "drivers/net/ethernet/marvell/octeontx2/af/cn20k/api.h",
                        "drivers/net/ethernet/marvell/octeontx2/af/cn20k/mbox_init.c",
                        "drivers/net/ethernet/marvell/octeontx2/af/rvu.c"
                    ],
                    "versions": [
                        {
                            "version": "6.17",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.17",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.57",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.6",
                            "lessThanOrEqual": "7.2.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.3",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }