ata: Migrate CONFIG_DWC_AHSATA to Kconfig

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index 2eab570..25ef5ce 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -47,6 +47,12 @@
 	  Enable this driver to support Sata devices through
 	  Synopsys DWC AHCI module.
 
+config DWC_AHSATA
+	bool "Enable DWC AHSATA driver support"
+	help
+	  Enable this driver to support the DWC AHSATA SATA controller found
+	  in i.MX5 and i.MX6 SoCs.
+
 config FSL_SATA
 	bool "Enable Freescale SATA controller driver support"
 	help