ARMv8.5 MTE: Make strchr-mte big and little endian compatible.

Previously used LDR istrunction resulted little endian behavior.
This LD1 results byte-by-byte load.

Testing done:
optimized-routines/string/test/memchr.c
  Big Endian test: qemu-aarch64_be
Booted nanodroid with MTE enabled.
bionic string tests with MTE enabled.
1 file changed