x86/mm: Completely drop the TLB flush from ptep_set_access_flags()

x86/mm: Completely drop the TLB flush from ptep_set_access_flags()

Intel has an architectural guarantee that the TLB entry causing
a page fault gets invalidated automatically. This means
we should be able to drop the local TLB invalidation.

Because of the way other areas of the page fault code work,
chances are good that all x86 CPUs do this.  However, if
someone somewhere has an x86 CPU that does not invalidate
the TLB entry causing a page fault, this one-liner should
be easy to revert - or a CPU model specific quirk could
be added to retain this optimization on most CPUs.

Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Linus Torvalds <torvalds@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michel Lespinasse <walken@google.com>
[ Applied changelog massage and moved this last in the series,
  to create bisection distance. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>