i9300: audio: don't disable back mic upon voice call end

Back or Secondary Microphone (Sub Mic) is turned on and off
using noise_suppression parameter from adev_set_parameters
and hence it is not required to disable the back mic explicitly
in voicecall_default_disable

Change-Id: I0959bfb0d49c0ba75795f5374e6f5ba5eac59cf1

Patchset: 1
http://review.cyanogenmod.org/#/c/51157/
i9300: audio: properly set routing and standby after voice call

Disabling the voice call route using voicecall_default_disable is not
sufficient since there are additional routes which are used during a
voice call, which have to be properly disabled. Also, set the input
device to standy which prevents the mic from not working for the
first time after a voice call.

This could also serve a potential fix for battery drain issues after
voice call.

Change-Id: I0acd41deafd49da50857d6fe6396c3b5270d911c

Patchset: 4
http://review.cyanogenmod.org/#/c/51085/