dmaengine: Use Pointer xt after NULL check.

Removing static analysis error:-
Possible null pointer dereference: xt

Because currently xt is dereferenced before NULL check,
Thus Use it after NULL Check.
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Reviewed-by: Vaneet Narang <v.narang@samsung.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/at_hdmac.c

@@ -659,14 +659,14 @@ atc_prep_dma_interleaved(struct dma_chan *chan,
 	size_t			len = 0;
 	int			i;
 
+	if (unlikely(!xt || xt->numf != 1 || !xt->frame_size))
+		return NULL;
+
 	dev_info(chan2dev(chan),
 		 "%s: src=0x%08x, dest=0x%08x, numf=%d, frame_size=%d, flags=0x%lx\n",
 		__func__, xt->src_start, xt->dst_start, xt->numf,
 		xt->frame_size, flags);
 
-	if (unlikely(!xt || xt->numf != 1 || !xt->frame_size))
-		return NULL;
-
 	/*
 	 * The controller can only "skip" X bytes every Y bytes, so we
 	 * need to make sure we are given a template that fit that