usb: musb: Balance list entry in musb_gadget_queue

usb: musb: Balance list entry in musb_gadget_queue

musb_gadget_queue() adds the passed request to musb_ep::req_list. If the
endpoint is idle and it is the first request then it invokes
musb_queue_resume_work(). If the function returns an error then the
error is passed to the caller without any clean-up and the request
remains enqueued on the list. If the caller enqueues the request again
then the list corrupts.

Remove the request from the list on error.

Fixes: ea2f35c01d5ea ("usb: musb: Fix sleeping function called from invalid context for hdrc glue")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Viraj Shah <viraj.shah@linutronix.de>
Link: https://lore.kernel.org/r/20211021093644.4734-1-viraj.shah@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>