x86: Add Moorestown early detection

Moorestown MID devices need to be detected early in the boot process
to setup and do not call x86_default_early_setup as there is no EBDA
region to reserve.

[ Copied the minimal code from Jacobs latest MRST series ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jacob Pan <jacob.jun.pan@intel.com>