Intel MID i2s test: MID i2s ssp test driver

Intel MID i2s test: MID i2s ssp test driver

BZ: 12606

Add a "mid_i2s_ssp" miscdevice for Intel MID I2S on SSP loopback tests.
It allows testing the I2S link between Penwell SSP and Modem or Bluetooth chip.
Device can be configured using ioctls from user-space.

Change-Id: I6704389493bb31c69ba5ae119f0aeedc18bc2e38
Signed-off-by: Renaud de Chivre <renaudx.de.chivre@intel.com>
Signed-off-by: David Wagner <davidx.wagner@intel.com>
Reviewed-on: http://android.intel.com:8080/27794
Tested-by: Barthes, FabienX <fabienx.barthes@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>