ALSA: cirrus: Tidy up of firmware control read/write

Merge series from Richard Fitzgerald <rf@opensource.cirrus.com>:

This set of patches factors out some repeated code to clean up
firmware control read/write functions, and removes some redundant
control notification code.

base-commit: f193957b0fbbba397c8bddedf158b3bf7e4850fc

diff --cc drivers/firmware/cirrus/cs_dsp.c
Simple merge

diff --cc include/linux/firmware/cirrus/cs_dsp.h
Simple merge

diff --cc sound/soc/codecs/wm_adsp.c
Simple merge