Add Google hammer HID driver. This driver allow us to control hammer
keyboard backlight and support future features.
Signed-off-by: NWei-Ning Huang <wnhuang@google.com>
Signed-off-by: NNicolas Boichat <drinkcat@chromium.org>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>