it821x: Add ultra_mask quirk for Vortex86SX

On Vortex86SX with IDE controller revision 0x11 ultra DMA must be
disabled. This patch was tested by DMP and seems to work.

It is a cleaned up version of their older Kernel patch: 
 http://www.dmp.com.tw/tech/vortex86sx/patch-2.6.24-DMP.gz

Tested-by: Shawn Lin <shawn@dmp.com.tw>
Signed-off-by: Brandon Philips <bphilips@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>