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

This patch is to support Freescale sata driver with dts initialized.
Also resolved the following problems.

===================== WARNING ======================
This board does not use CONFIG_DM_SCSI. Please update
the storage controller to use CONFIG_DM_SCSI 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: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index 4e95a68..87636ae 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -59,6 +59,16 @@
 	  Enable this driver to support Sata devices through
 	  Synopsys DWC AHCI module.
 
+config FSL_AHCI
+	bool "Enable Freescale AHCI driver support"
+	select SCSI_AHCI
+	depends on AHCI
+	depends on DM_SCSI
+	help
+	  Enable this driver to support Sata devices found in
+	  some Freescale PowerPC SoCs.
+
+
 config DWC_AHSATA
 	bool "Enable DWC AHSATA driver support"
 	select LIBATA