libata: Add pata_atp867x driver for Artop/Acard ATP867X controllers

This is a new pata driver for ARTOP 867X 64bit 4-channel UDMA133 ATA ctrls.
Based on the Atp867 data sheet rev 1.2, Acard, and in part on early ide codes
from Eric Uhrhane <ericu@google.com>.

Signed-off-by: John(Jung-Ik) Lee <jilee@google.com>
Reviewed-by:  Grant Grundler <grundler@google.com>
Reviewed-by:  Gwendal Gringo <gwendal@google.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>