dmaengine: intel_mid_dma: fix error status mask

The error status mask (MASK_ERR) has the same format as the other
masks (MASK_TFR, MASK_BLOCK etc) and must be cleared the same way.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>