mfd: Fix asic3 based SD card resume after suspend

The mfd/asic3 driver did not define the suspend/resume handlers for the mmc cell
driver. Consequently the mmc driver did not resume properly after returning from
suspend, making sd cards unusable and preventing suspend from being entered a
second time. This patch adds the suspend/resume handlers, fixing the problem.

Signed-off-by: Paul Parsons <lost.distance@yahoo.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>