mixer_paths: work around loss of BT call audio

Move common voice controls from RX to TX devices to work around
weird AUX_PCM dependency on "QUAT_MI2S_RX Port Mixer SLIM_1_TX"

Bug: 19099854

Change-Id: I8c9d0210c1c6cb925b28ba291adc113c1db2db26
1 file changed