r_submix HAL: remove legacy code for in-pipe conversions

Old hacky uses of this HAL required channel and sample
rate conversion, which were never expected when this HAL
is used for its real application as the backend for
dynamic audio policies. In that context conversions are
performed in audio_flinger in the mixer.

Bug: 141604269
Test: atest AudioHostTest#testTwoChannelCapturing

Change-Id: I333e981fb3db403ab2da6f77debe49bc7d132ebc
1 file changed