dmaengine: Revert "dmaengine: mic_x100: add missing spin_unlock"

This reverts commit e958e079 ("dmaengine: mic_x100: add missing
spin_unlock").

The above patch is incorrect. There is nothing wrong with the original
code. The spin_lock is acquired in the "prep" functions and released
in "submit".

Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>