x86/entry: Fix AC assertion

x86/entry: Fix AC assertion

The WARN added in commit 3c73b81a9164 ("x86/entry, selftests: Further
improve user entry sanity checks") unconditionally triggers on a IVB
machine because it does not support SMAP.

For !SMAP hardware the CLAC/STAC instructions are patched out and thus if
userspace sets AC, it is still have set after entry.

Fixes: 3c73b81a9164 ("x86/entry, selftests: Further improve user entry sanity checks")
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Daniel Thompson <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]