x86/mm: Remove stale comment about KMEMCHECK

x86/mm: Remove stale comment about KMEMCHECK

This comment referred to a conditional call to kmemcheck_hide() that was
here until commit 4950276672fc ("kmemcheck: remove annotations").

Now that kmemcheck has been removed, it doesn't make sense anymore.

Signed-off-by: Jann Horn <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>