HID: hid-lg: Check return values from lg[N]ff_init()

Check return values from lg[N]ff_init(). hid-lg did not check return values from
the lg[N]_init() functions, possibly trying to work with a device whose
initialization has failed.

Signed-off-by: Michal Malý <madcatxster@devoid-pointer.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>