Merge "Audio r_submix : Handle the usecase when no data is available to read." into main am: 0bc307a5dd

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2686486

Change-Id: I2c42b7029dc17c57fe14db15bbd57891c6e7ff53
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>