libc: delete x86 memchr.S

This file is never used.

Change-Id: Ief08ad176713b5194048852609613801969e1364
Merge "libc: delete x86 memchr.S"
libc x86: Remove index.S, strcpy.S, strchr.S

These files are never used.

Change-Id: Iab8474bdff3bd4d225597c62b3c0f0849f808818
Merge "libc x86: Remove index.S, strcpy.S, strchr.S"
Merge remote-tracking branch 'aosp/master'