dmaengine: edma: predecence bug in GET_NUM_QDMACH()

The current code uses bits 0-2 instead of 4-6 as the comment says.

Fixes: 633e42b8 ('dmaengine: edma: Get qDMA channel information from HW also')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>