st-hal: force to reset backend for device switch

Device reset can be ignored during device switch as it's
consecutively needed by audio recording during concurrency.
For example, when VA switches device from dual mic to
headset mic, path of dual mic won't get reset, so mixer
ctl like "VA_CDC_DMA_TX_0 Channels" is still left as 2.
To fix this, set the flag to reset previous device though
it is still needed by audio recording, as recording will
finally switch to the same device as VA.

Change-Id: If3269a703e9d43de30e4521c1f7f130b5cc749d5
1 file changed