Clean up and fix Krait cflags

For krait, we were using the cortex-a15 cflags for GCC, but a completely
separate set for Clang. To make it more readable, and prevent the LPAE
flag from being missed for Clang, explicitly define krait cflags for GCC
as well.

Change-Id: I6dc00a22e2b298ee3755190bf09f28e427c8c70d
1 file changed