ASoc: simple-mux: Allow to specify an idle-state

Merge series from "Hendrik v. Raven" <h.v.raven@merzmedtech.de>:

This series adds support for the idle-state property from the mux
framework to the simple-mux audio variant. It allows to specify the state
of the mux when it is not in use.

diff --cc MAINTAINERS
Simple merge

diff --cc include/linux/soundwire/sdw_intel.h
Simple merge