audio remote submix: fix write blocked on input standby

Do not block in out_write() when the peer input is in standby to avoid
remaining stuck when writing to the blocking mono pipe.

Bug: 141878993
Test: atest AudioHostTest#testTwoChannelCapturing

Change-Id: Ie92d59529ac1018a6785c3ac31696dcccdbb204a
Merged-In: Ie92d59529ac1018a6785c3ac31696dcccdbb204a
1 file changed