Add explicit key mappings for TwinHan USB HID remote control.

All dummy Ctrl, Alt, Meta, ... key press/release events generated
by the remote are silenced by "unmapping" them. This makes Power and
Volume keys single-key and strips the regular (even while idle) key
release events for Ctrl, Alt, Meta, ...
Signed-off-by: NBruno Premont <bonbons@linux-vserver.org>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>