ASoC: msmcobalt: Check for number of aux codecs

Add a check for number of aux codecs before applying the
aux codec gain settings from machine driver to avoid
setting the gains if there are no aux codecs connected.

Change-Id: I86e6c4a15e6eed8e4650c6eb072f07f49890aecc
Signed-off-by: Sudheer Papothi <spapothi@codeaurora.org>