audio: enable compilation of qahw_api on Android builds

-Fix compilation errors from qahw_api tests and enable
 compilation of qahw_api on Android builds.

Change-Id: Ifc05ea22f0fd9ac0e6f6e9b22a6c593841acc761
diff --git a/qahw_api/test/Makefile.am b/qahw_api/test/Makefile.am
index 5378e0b..abccdce 100644
--- a/qahw_api/test/Makefile.am
+++ b/qahw_api/test/Makefile.am
@@ -1,12 +1,12 @@
 bin_PROGRAMS = hal_play_test
 
 PLAY_CPPFLAGS = -Wno-sign-compare -Werror
+PLAY_CPPFLAGS += -D__unused=__attribute__\(\(__unused__\)\)
 PLAY_INCLUDES = -I $(top_srcdir)/qahw_api/inc
 
 hal_play_test_SOURCES = qahw_playback_test.c \
                         qahw_effect_test.c
 hal_play_test_CPPFLAGS = $(PLAY_CPPFLAGS) $(PLAY_INCLUDES)
-hal_play_test_CPPFLAGS += -D__unused=__attribute__\(\(__unused__\)\)
 hal_play_test_LDADD = -lutils ../libqahw.la