usb: gadget: f_hid: fix refcount leak on error path

When failing to allocate report_desc, opts->refcnt has already been
incremented so it needs to be decremented to avoid leaving the options
structure permanently locked.

Fixes: 21a9476a ("usb: gadget: hid: add configfs support")
Tested-by: Lee Jones <lee@kernel.org>
Reviewed-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Reviewed-by: Lee Jones <lee@kernel.org>
Signed-off-by: John Keeping <john@metanate.com>
Link: https://lore.kernel.org/r/20221122123523.3068034-3-john@metanate.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/function/f_hid.c

@@ -1292,6 +1292,7 @@ static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
 						 GFP_KERNEL);
 		if (!hidg->report_desc) {
 			put_device(&hidg->dev);
+			--opts->refcnt;
 			mutex_unlock(&opts->lock);
 			return ERR_PTR(-ENOMEM);
 		}