ata: Migrate CONFIG_SCSI_AHCI to Kconfig

And use 'imply' liberally.

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
diff --git a/arch/arm/cpu/armv8/fsl-layerscape/Kconfig b/arch/arm/cpu/armv8/fsl-layerscape/Kconfig
index 5a75920..66bc32c 100644
--- a/arch/arm/cpu/armv8/fsl-layerscape/Kconfig
+++ b/arch/arm/cpu/armv8/fsl-layerscape/Kconfig
@@ -35,6 +35,7 @@
 	select ARCH_EARLY_INIT_R
 	select BOARD_EARLY_INIT_F
 	imply SCSI
+	imply SCSI_AHCI
 	imply CMD_PCI
 
 config ARCH_LS1046A
@@ -61,6 +62,7 @@
 	select ARCH_EARLY_INIT_R
 	select BOARD_EARLY_INIT_F
 	imply SCSI
+	imply SCSI_AHCI
 
 config ARCH_LS1088A
 	bool