n7100: audio: disable voicecall route on init and leaving incall state

Original Change-Id in I9300 tree: I5e1ca99f19a715ef509825d46103c60f10d35ce2

Change-Id: I4b3f42ab561dd260d20507f04b1c4398cd07154b
n7100: 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

Original Change-Id in i9300 tree: I0959bfb0d49c0ba75795f5374e6f5ba5eac59cf1

Change-Id: Ie03d8515df11d276d0ac4c0db05be1d9dbb82089
n7100: 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.

Original Change-Id in i9300 tree: I0acd41deafd49da50857d6fe6396c3b5270d911c

Change-Id: Id2a0e4f22baca54b0ae7cf775aff6cf5c5b0bd14