rtlwifi: prevent memory leak in rtl_usb_probe

In rtl_usb_probe if allocation for usb_data fails the allocated hw
should be released. In addition the allocated rtlpriv->usb_data should
be released on error handling path.

Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>