dmaengine: ti: k3-udma: Fix compiler warning in udma_get_chan_pair

Fixes:
drivers/dma/ti/k3-udma.c: In function ‘udma_get_chan_pair’:
drivers/dma/ti/k3-udma.c:1219:39: warning: initialization discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  struct udma_match_data *match_data = ud->match_data;
                                       ^~

Reported-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>

drivers/dma/ti/k3-udma.c

@@ -1216,7 +1216,7 @@ static int udma_get_rchan(struct udma_chan *uc)
 static int udma_get_chan_pair(struct udma_chan *uc)
 {
 	struct udma_dev *ud = uc->ud;
-	struct udma_match_data *match_data = ud->match_data;
+	const struct udma_match_data *match_data = ud->match_data;
 	int chan_id, end;
 
 	if ((uc->tchan && uc->rchan) && uc->tchan->id == uc->rchan->id) {