usb: gadget: u_ether: Set is_suspend flag if remote wakeup fails

Currently while UDC suspends, u_ether attempts to remote wakeup
the host if there are any pending transfers. However, if remote
wakeup fails, the UDC remains suspended but the is_suspend flag
is not set. And since is_suspend flag isn't set, the subsequent
eth_start_xmit() would queue USB requests to suspended UDC.

To fix this, bail out from gether_suspend() only if remote wakeup
operation is successful.

Cc: stable <stable@kernel.org>
Fixes: 0a1af6d ("usb: gadget: f_ecm: Add suspend/resume and remote wakeup support")
Signed-off-by: Prashanth K <prashanth.k@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250212100840.3812153-1-prashanth.k@oss.qualcomm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Prashanth K

drivers/usb/gadget/function/u_ether.c

@@ -1052,8 +1052,8 @@ void gether_suspend(struct gether *link)
 		 * There is a transfer in progress. So we trigger a remote
 		 * wakeup to inform the host.
 		 */
-		ether_wakeup_host(dev->port_usb);
-		return;
+		if (!ether_wakeup_host(dev->port_usb))
+			return;
 	}
 	spin_lock_irqsave(&dev->lock, flags);
 	link->is_suspend = true;