audio: Use hardcoded r_submix configuration with XML am: fc35ca3d32

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2794109

Change-Id: I7e9a2d481a5af5571fbf2957f6078db8ec157229
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>