dmaengine: ti: omap-dma: Remove 'Assignment in if condition'

While the compiler does not have problem with how it is implemented,
checkpatch does give en ERROR for this arrangement.

Signed-off-by: Peter Ujfalusi <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/ti/omap-dma.c

···
 	dma_cookie_t cookie, struct dma_tx_state *txstate)
 {
 	struct omap_chan *c = to_omap_dma_chan(chan);
-	struct virt_dma_desc *vd;
 	enum dma_status ret;
 	unsigned long flags;
 	struct omap_desc *d = NULL;
···
 			pos = 0;
 
 		txstate->residue = omap_dma_desc_size_pos(d, pos);
-	} else if ((vd = vchan_find_desc(&c->vc, cookie))) {
-		txstate->residue = omap_dma_desc_size(to_omap_dma_desc(&vd->tx));
 	} else {
-		txstate->residue = 0;
+		struct virt_dma_desc *vd = vchan_find_desc(&c->vc, cookie);
+
+		if (vd)
+			txstate->residue = omap_dma_desc_size(
+						to_omap_dma_desc(&vd->tx));
+		else
+			txstate->residue = 0;
 	}
 
 out: