carl9170: fix leaks at failure path in carl9170_usb_probe()

carl9170_usb_probe() does not handle request_firmware_nowait() failure
that leads to several leaks in this case.
The patch adds all required deallocations.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: John W. Linville <linville@tuxdriver.com>