dma: mv_xor: Remove unneeded NULL address check

This mmio address is checked at probe-time, which makes this test
redundant. Let's just remove it.
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/dma/mv_xor.c

@@ -1035,10 +1035,6 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
 	}
 
 	mv_chan->mmr_base = xordev->xor_base;
-	if (!mv_chan->mmr_base) {
-		ret = -ENOMEM;
-		goto err_free_dma;
-	}
 	tasklet_init(&mv_chan->irq_tasklet, mv_xor_tasklet, (unsigned long)
 		     mv_chan);