Use audio_channel_mask_t consistently

Change-Id: Ib832c0b707b1e0b82adf4ab3d4d18a2dc459d240
diff --git a/include/hardware/audio_policy.h b/include/hardware/audio_policy.h
index 78a1a62..8924dd1 100644
--- a/include/hardware/audio_policy.h
+++ b/include/hardware/audio_policy.h
@@ -132,7 +132,7 @@
                                     audio_stream_type_t stream,
                                     uint32_t samplingRate,
                                     audio_format_t format,
-                                    uint32_t channels,
+                                    audio_channel_mask_t channelMask,
                                     audio_output_flags_t flags);
 
     /* indicates to the audio policy manager that the output starts being used
@@ -157,7 +157,7 @@
     audio_io_handle_t (*get_input)(struct audio_policy *pol, audio_source_t inputSource,
                                    uint32_t samplingRate,
                                    audio_format_t format,
-                                   uint32_t channels,
+                                   audio_channel_mask_t channelMask,
                                    audio_in_acoustics_t acoustics);
 
     /* indicates to the audio policy manager that the input starts being used */