ata: Migrate CONFIG_SCSI_AHCI to Kconfig

And use 'imply' liberally.

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
diff --git a/configs/A10-OLinuXino-Lime_defconfig b/configs/A10-OLinuXino-Lime_defconfig
index 30e846c..ff1d35b 100644
--- a/configs/A10-OLinuXino-Lime_defconfig
+++ b/configs/A10-OLinuXino-Lime_defconfig
@@ -17,6 +17,7 @@
 # CONFIG_SPL_DOS_PARTITION is not set
 # CONFIG_SPL_ISO_PARTITION is not set
 # CONFIG_SPL_EFI_PARTITION is not set
+CONFIG_SCSI_AHCI=y
 CONFIG_SUN4I_EMAC=y
 CONFIG_AXP_ALDO3_VOLT=2800
 CONFIG_AXP_ALDO4_VOLT=2800