Revert "ata: fsl_ahci: Add sata DM support for Freescale powerpc socs"

This reverts commit 1ee49429.

Commit 1ee49429 ("ata: fsl_ahci: Add sata DM support for Freescale
powerpc socs") introduced SCSI layer to call AHCI private API in order
to support sata operations, In DM mode, This is not necessary for
non-AHCI sata. So revert it and have already updated the driver itself
to operate sata directly.

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