platform/x86: winmate-fm07-keys: Winmate FM07/FM07P buttons

Winmate FM07 and FM07P in-vehicle computers have a row of five buttons
below the display. This module adds an input device that delivers key
events when these buttons are pressed.

Signed-off-by: Daniel Beer <daniel.beer@tirotech.co.nz>
Link: https://lore.kernel.org/r/623a110a.1c69fb81.64f39.0118@mx.google.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>