usb: musb: host: release dma channels if no active io

Currently DMA channels are allocated and they remain allocated
even if there is no active data transfer. Added channel_release()
whenever there is no pending request.
Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/musb_host.c

@@ -375,11 +375,21 @@ static void musb_advance_schedule(struct musb *musb, struct urb *urb,
 	 */
 	if (list_empty(&qh->hep->urb_list)) {
 		struct list_head	*head;
+		struct dma_controller	*dma = musb->dma_controller;
 
-		if (is_in)
+		if (is_in) {
 			ep->rx_reinit = 1;
-		else
+			if (ep->rx_channel) {
+				dma->channel_release(ep->rx_channel);
+				ep->rx_channel = NULL;
+			}
+		} else {
 			ep->tx_reinit = 1;
+			if (ep->tx_channel) {
+				dma->channel_release(ep->tx_channel);
+				ep->tx_channel = NULL;
+			}
+		}
 
 		/* Clobber old pointers to this qh */
 		musb_ep_set_qh(ep, is_in, NULL);