Android.mk: remove unnecessary -llog reference

nothing is using android/log.h currently; also quiets a warning when
building a static lib:
Android NDK: WARNING:libvpx/build/make/Android.mk:vpx: LOCAL_LDLIBS is
always ignored for static libraries

Change-Id: I1469a5d6fca4f7338a4a82e26a03e60fc91d92ca
1 file changed