pata_arasan_cf: Adding support for arasan compact flash host controller

The Arasan CompactFlash Device Controller has three basic modes of
operation: PC card ATA using I/O mode, PC card ATA using memory mode, PC card
ATA using true IDE modes.

Currently driver supports only True IDE mode.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>