usb: gadget: free opts struct on error recovery

usb: gadget: free opts struct on error recovery

Fix memory leaks introduced in commits:

3cb4fda5adde4ca64a0b9a168a790392d9df3688
usb: gadget: f_ncm: convert to new function interface with backward compatibility

507010bc7c26c5da2b820543c0551074819f85aa
usb: gadget: f_ecm: convert to new function interface with backward compatibility

92dbb36e55b466b0a6c48c85f45265db21b39197
usb: gadget: f_phonet: convert to new function interface with backward compatibility

050a391f2e283911f102eca1bb130515f09cb6f2
usb: gadget: f_eem: convert to new function interface with backward compatibility

66fccfe5900c28606340beef5c38a47dd95d2768
usb: gadget: f_subset: convert to new function interface with backward compatibility

e1f7dd1b5780775d626c0a1f92ec5a6d948712c0
usb: gadget: f_rndis: convert to new function interface with backward compatibility

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>