HID: hid-lg4ff: Remove unused variable from the "lg4ff_device_entry" struct.

Remove unused variable from the "lg4ff_device_entry" struct. This is a leftover
from times where hid_get|set_drvdata() was not available to hid-lg4ff so it had
to keep track of the devices it managed by itself.

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

diff --cc drivers/hid/hid-lg4ff.c
Simple merge