usb: dwc3: gadget: Don't disconnect if not started

Don't go through soft-disconnection sequence if the controller hasn't
started. Otherwise, there will be timeout and warning reports from the
soft-disconnection flow.

Cc: stable@vger.kernel.org
Fixes: 61a3488 ("usb: dwc3: gadget: Fix NULL pointer dereference in dwc3_gadget_suspend")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/linux-usb/20240215233536.7yejlj3zzkl23vjd@synopsys.com/T/#mb0661cd5f9272602af390c18392b9a36da4f96e6
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/e3be9b929934e0680a6f4b8f6eb11b18ae9c7e07.1708043922.git.Thinh.Nguyen@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Thinh Nguyen

drivers/usb/dwc3/gadget.c

@@ -2650,6 +2650,11 @@ static int dwc3_gadget_soft_disconnect(struct dwc3 *dwc)
 	int ret;
 
 	spin_lock_irqsave(&dwc->lock, flags);
+	if (!dwc->pullups_connected) {
+		spin_unlock_irqrestore(&dwc->lock, flags);
+		return 0;
+	}
+
 	dwc->connected = false;
 
 	/*