Use standard name and type for channel mask

Former name 'channels' was ambiguous with respect to channel count.

Change-Id: I716f792d95a7e0c787d27514ad6e93dbcef8a415
diff --git a/media/libmedia/IAudioFlingerClient.cpp b/media/libmedia/IAudioFlingerClient.cpp
index 2d1e0f8..84a589a 100644
--- a/media/libmedia/IAudioFlingerClient.cpp
+++ b/media/libmedia/IAudioFlingerClient.cpp
@@ -54,7 +54,7 @@
                     (const AudioSystem::OutputDescriptor *)param2;
             data.writeInt32(desc->samplingRate);
             data.writeInt32(desc->format);
-            data.writeInt32(desc->channels);
+            data.writeInt32(desc->channelMask);
             data.writeInt32(desc->frameCount);
             data.writeInt32(desc->latency);
         }
@@ -84,7 +84,7 @@
             } else if (event != AudioSystem::OUTPUT_CLOSED && event != AudioSystem::INPUT_CLOSED) {
                 desc.samplingRate = data.readInt32();
                 desc.format = data.readInt32();
-                desc.channels = data.readInt32();
+                desc.channelMask = (audio_channel_mask_t) data.readInt32();
                 desc.frameCount = data.readInt32();
                 desc.latency = data.readInt32();
                 param2 = &desc;