drivers: most: add ALSA sound driver

This patch moves the ALSA sound driver out of the staging area and adds it
to the stable part of the MOST driver. Modifications to the Makefiles and
Kconfigs are done accordingly to not break the build.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Link: https://lore.kernel.org/r/1612865627-29950-1-git-send-email-christian.gromm@microchip.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>