usb: gadget: f_hid: use after free in hidg_alloc_inst()

We free "opts" on the error path and then dereference it.

Fixes: 21a9476a ('usb: gadget: hid: add configfs support')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>