tools headers: Update the copy of x86's mem{cpy,set}_64.S used in 'perf bench'

This is to get the changes from:

  68674f94 ("x86: don't use REP_GOOD or ERMS for small memory copies")
  20f3337d ("x86: don't use REP_GOOD or ERMS for small memory clearing")

This also make the 'perf bench mem' files stop referring to the erms
versions that gone away with the above patches.

That addresses these perf tools build warning:

  Warning: Kernel ABI header at 'tools/arch/x86/lib/memcpy_64.S' differs from latest version at 'arch/x86/lib/memcpy_64.S'
  diff -u tools/arch/x86/lib/memcpy_64.S arch/x86/lib/memcpy_64.S
  Warning: Kernel ABI header at 'tools/arch/x86/lib/memset_64.S' differs from latest version at 'arch/x86/lib/memset_64.S'
  diff -u tools/arch/x86/lib/memset_64.S arch/x86/lib/memset_64.S

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>