dmaengine: edma: Move the pending error check into helper function

In the ccerr interrupt handler the code checks for pending errors in the
error status registers in two different places.
Move the check out to a helper function.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>