dma: remove unnecessary null pointer check in mmp_pdma.c

the pointer cfg is dereferenced in line 594, so it's no reason to check null
again in line 620.
Signed-off-by: Cong Ding <dinggnu@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/mmp_pdma.c

@@ -617,10 +617,8 @@ static int mmp_pdma_control(struct dma_chan *dchan, enum dma_ctrl_cmd cmd,
 		else if (maxburst == 32)
 			chan->dcmd |= DCMD_BURST32;
 
-		if (cfg) {
 		chan->dir = cfg->direction;
 		chan->drcmr = cfg->slave_id;
-		}
 		chan->dev_addr = addr;
 		break;
 	default: