usb: gadget: f_mass_storage: simplify start_transfer slightly

Flatten the start_transfer function by reversing the if condition and
returning early out of the function if everything went fine.  It makes
the function look less complicated, at least to me, and easier to
understand.
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/f_mass_storage.c

@@ -566,8 +566,11 @@ static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
 	*pbusy = 1;
 	*state = BUF_STATE_BUSY;
 	spin_unlock_irq(&fsg->common->lock);
+
 	rc = usb_ep_queue(ep, req, GFP_KERNEL);
-	if (rc != 0) {
+	if (rc == 0)
+		return;  /* All good, we're done */
+
 	*pbusy = 0;
 	*state = BUF_STATE_EMPTY;
 
@@ -577,11 +580,8 @@ static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
 	 * Note: currently the net2280 driver fails zero-length
 	 * submissions if DMA is enabled.
 	 */
-		if (rc != -ESHUTDOWN &&
-		    !(rc == -EOPNOTSUPP && req->length == 0))
-			WARNING(fsg, "error in submission: %s --> %d\n",
-				ep->name, rc);
-	}
+	if (rc != -ESHUTDOWN && !(rc == -EOPNOTSUPP && req->length == 0))
+		WARNING(fsg, "error in submission: %s --> %d\n", ep->name, rc);
 }
 
 static bool start_in_transfer(struct fsg_common *common, struct fsg_buffhd *bh)
@@ -3665,4 +3665,3 @@ void fsg_config_from_params(struct fsg_config *cfg,
 	cfg->fsg_num_buffers = fsg_num_buffers;
 }
 EXPORT_SYMBOL_GPL(fsg_config_from_params);
-