USB: musb: gadget_ep0: avoid SetupEnd interrupt

Gadget stalling a zero-length SETUP request results in this error message:

SetupEnd came in a wrong ep0stage idle

In order to avoid it, always set the CSR0.DataEnd bit after detecting a zero-
length request.  Add the missing '\n' to the error message itself as well...
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Acked-by: Anand Gadiyar <gadiyar@ti.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/musb/musb_gadget_ep0.c

@@ -664,7 +664,7 @@ irqreturn_t musb_g_ep0_irq(struct musb *musb)
 			musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
 			break;
 		default:
-			ERR("SetupEnd came in a wrong ep0stage %s",
+			ERR("SetupEnd came in a wrong ep0stage %s\n",
 			    decode_ep0stage(musb->ep0_state));
 		}
 		csr = musb_readw(regs, MUSB_CSR0);
@@ -787,12 +787,18 @@ setup:
 				handled = service_zero_data_request(
 						musb, &setup);
 
-				/* status stage might be immediate */
-				if (handled > 0) {
+				/*
+				 * We're expecting no data in any case, so
+				 * always set the DATAEND bit -- doing this
+				 * here helps avoid SetupEnd interrupt coming
+				 * in the idle stage when we're stalling...
+				 */
 				musb->ackpend |= MUSB_CSR0_P_DATAEND;
+
+				/* status stage might be immediate */
+				if (handled > 0)
 					musb->ep0_state =
 						MUSB_EP0_STAGE_STATUSIN;
-				}
 				break;
 
 			/* sequence #1 (IN to host), includes GET_STATUS