alienware-wmi: Add support for new platform: X51-R3

The X51-R3 is in the X51 family.  It includes 3 internal
lighting zones as well as is the first AW desktop that
includes support for a graphics amplifier.

Signed-off-by: Mario Limonciello <mario_limonciello@dell.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>