Use audio_channel_mask_t consistently

Change-Id: I77a624e2656046075eb38cf880c26cdf8ba36af8
diff --git a/src/android/android_sles_conversions.h b/src/android/android_sles_conversions.h
index 6a27dc0..9f6aac4 100644
--- a/src/android/android_sles_conversions.h
+++ b/src/android/android_sles_conversions.h
@@ -62,13 +62,13 @@
 }
 
 
-static inline int sles_to_android_channelMaskIn(SLuint32 nbChannels, SLuint32 channelMask) {
+static inline audio_channel_mask_t sles_to_android_channelMaskIn(SLuint32 nbChannels, SLuint32 channelMask) {
     // FIXME handle channel mask mapping between SL ES and Android
     return audio_channel_in_mask_from_count(nbChannels);
 }
 
 
-static inline int sles_to_android_channelMaskOut(SLuint32 nbChannels, SLuint32 channelMask) {
+static inline audio_channel_mask_t sles_to_android_channelMaskOut(SLuint32 nbChannels, SLuint32 channelMask) {
     // FIXME handle channel mask mapping between SL ES and Android
     return audio_channel_out_mask_from_count(nbChannels);
 }