[ARM] pata_pxa: DMA-capable PATA driver

This patch adds a driver for a harddrive attached to PXA address and data bus.
Unlike pata_platform, this driver allows usage of PXA DMA controller, making the
transmission speed 3x higher.

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>