dma: edma: Fix memory leak

When it fails to allocate a slot, edesc should be free'd before return;
Signed-off-by: Valentin Ilie <valentin.ilie@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/edma.c

@@ -305,6 +305,7 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg(
 				edma_alloc_slot(EDMA_CTLR(echan->ch_num),
 						EDMA_SLOT_ANY);
 			if (echan->slot[i] < 0) {
+				kfree(edesc);
 				dev_err(dev, "Failed to allocate slot\n");
 				kfree(edesc);
 				return NULL;