Mixer: Handle write element

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Mixer: Set the next elements routes when one failed

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>

Conflicts:

	tinyalsa_audio/mixer.c
Merge "Mixer: Handle write element" into cm-10.1
Merge "Mixer: Set the next elements routes when one failed" into cm-10.1