CVE-2021-47430 x86/entry: Clear X86_FEATURE_SMAP when CONFIG_X86_SMAP=n

In the Linux kernel, the following vulnerability has been resolved: x86/entry: Clear X86FEATURESMAP when CONFIGX86SMAP=n Commit 3c73b81a9164 "x86/entry, selftests: Further improve user entry sanity checks" added a warning if AC is set when in the kernel. Commit 662a0221893a3d "x86/entry: Fix AC...