usb: dwc3: gadget: don't prevent gadget from being probed if we fail
usb: dwc3: gadget: don't prevent gadget from being probed if we fail

In case we fail our ->udc_start() callback, we
should be ready to accept another modprobe following
the failed one.

We had forgotten to clear dwc->gadget_driver back
to NULL and, because of that, we were preventing
gadget driver modprobe from being retried.

Cc: <4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org>
Signed-off-by: Felipe Balbi <94dddeeef08b001e003cce128ddc162a4e2c6cd2@ti.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs