ata: fsl_sata: Add DM support for Freescale PowerPC SATA driver

Add DM support for Freescale PowerPC sata driver used for PowerPC T series
SoCs,

CONFIG_BLK needs to be enabled on these platforms. It adds the SATA
controller as AHCI device, which is strictly speaking not correct,
as the controller is not AHCI compatible, But the U-Boot AHCI uclass
interface enables the usage of this DM driver,

Also fix below warning while PowerPC T series boards compilation,

===================== WARNING ======================"
This board does use CONFIG_LIBATA but has CONFIG_AHCI not"
enabled. Please update the storage controller driver to use"
CONFIG_AHCI before the v2019.07 release."
Failure to update by the deadline may result in board removal."
See doc/driver-model/MIGRATION.txt for more info."
===================================================="

Signed-off-by: Peng Ma <peng.ma@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>