Update AIDL<->legacy conversion for AudioChannelLayout

Index masks can contain arbitrary bits set, thus the range
of valid values is not restricted to AUDIO_CHANNEL_INDEX_MASK_*
values from system/audio.h.

Bug: 188932434
Bug: 195346865
Test: atest audio_aidl_conversion_tests
Test: atest android.media.cts.AudioNativeTest#testInputChannelMasks
Change-Id: Ic09c89c996726d9be4563c9d55327bbe9a5b199d