r_submix module: pipe size changes with sample rate

Adapt the pipe size based on the sample rate.
Behavior is unchanged for the default sample rate (48kHz), size
is adjusted by the ratio relative to the default rate.

Bug: 141604269
Test: atest AudioHostTest#testTwoChannelCapturingMediaConversion
Change-Id: I0ba45af18ef02dc0ef77d480e1203d2cd1db9864
1 file changed