zlib: Remove usage of cpu directive in inline asm

 * Clang will actually handle this fine by default, but
   GCC will not. On the other hand, Clang doesn't support
   the .cpu directive. Instead, set it as a CFLAG for arm64
   only, which makes everyone happy.

Change-Id: Ice5b62d43e81f13bd7d3e7a0b7afe4a547b2e758
2 files changed