The G920 can adjust the amount of 'turn' it permits, this patch adds
a sysfs file 'range' to control this.
Signed-off-by: Simon Wood <simon@mungewell.org>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>