ANDROID: Makefile: Properly resolve 4.9.169 merge

The merge removed commit 4dcb0afd ("ANDROID: Kbuild, LLVMLinux:
allow overriding clang target triple").

This keeps commit 1347aa2a ("kbuild: clang: choose GCC_TOOLCHAIN_DIR
not on LD"), which caused the conflict.

Change-Id: I72b7f69204a801ff6ef6405e24317a7b08428901
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>