hal: enable custom stereo for apq8009

Enable custom stereo to support dual mono for
apq8009.

Change-Id: Id95639a7422b5fb03964be99449fcaa961e7902b
Signed-off-by: Surendar karka <sukark@codeaurora.org>
diff --git a/configure.ac b/configure.ac
index 805d00c..6e03717 100644
--- a/configure.ac
+++ b/configure.ac
@@ -117,6 +117,7 @@
 AM_CONDITIONAL([DTSHD_PARSER], [test x$AUDIO_FEATURE_ENABLED_DTSHD_PARSER = xtrue])
 AM_CONDITIONAL([QAP], [test x$AUDIO_FEATURE_ENABLED_QAP = xtrue])
 AM_CONDITIONAL([AUDIO_HW_FFV], [test x$AUDIO_FEATURE_ENABLED_FFV = xtrue])
+AM_CONDITIONAL([CUSTOM_STEREO], [test x$AUDIO_FEATURE_ENABLED_CUSTOM_STEREO = xtrue])
 
 AC_CONFIG_FILES([ \
         Makefile \