ARM: davinci: da850: update SATA AHCI support

Update SATA AHCI support to make use of the new ahci_da850 host
driver (instead of the generic ahci_platform one) and remove
deprecated ahci_platform_data code.

Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>