ENGR00160862 unique id for each soc-audio device

ENGR00160862 unique id for each soc-audio device

On boards which have more than one soc-audio device, the initialization
of the first device will create a sysfs directory named
/sys/devices/platform/soc-audio and subsequent soc-audio devices will
fail to init because they try to create another sysfs directory of the
same name.

The solution is to have a unique number for each device such that
different boards having combinations will be OK.

Signed-off-by: Alan Tull <alan.tull@freescale.com>