pixelflinger: Fix local src arch includes

Automatic handling of LOCAL_SRC_FILES_(ARCH) was introduced in Android
5.0. Lower the SDK version check so these source files don't get
doubly included.

Change-Id: I8ebc7e3e687f2805f6ecb56499cbf39fc31e9545
Reference: see build/core/binary.mk and the handling of my_src_files
1 file changed