AudioSystem JNI: fix audio gain channel count

Use audio utility function instead of popcount
to get channel count from channel mask

Bug: 14815883.
Change-Id: Ia9a898c9f7f03d22caeefb418be1e33f65f7b7bb
diff --git a/core/jni/android_media_AudioSystem.cpp b/core/jni/android_media_AudioSystem.cpp
index 0f7e140..bf47dd3 100644
--- a/core/jni/android_media_AudioSystem.cpp
+++ b/core/jni/android_media_AudioSystem.cpp
@@ -613,8 +613,12 @@
                 goto exit;
             }
         }
-        //TODO: replace popcount by audio utils function mask to count
-        int numValues = popcount(nAudioPortConfig->gain.channel_mask);
+        int numValues;
+        if (useInMask) {
+            numValues = audio_channel_count_from_in_mask(nAudioPortConfig->gain.channel_mask);
+        } else {
+            numValues = audio_channel_count_from_out_mask(nAudioPortConfig->gain.channel_mask);
+        }
         jGainValues = env->NewIntArray(numValues);
         if (jGainValues == NULL) {
             ALOGV("convertAudioPortConfigFromNative could not create gain values %d", numValues);