ata: Migrate CONFIG_SATA_SIL3114 to Kconfig

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index 617c80f..77e0fbb 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -53,4 +53,9 @@
 	  Enable this driver to support the SIL3131, SIL3132 and SIL3124
 	  SATA controllers.
 
+config SATA_SIL3114
+	bool "Enable Silicon Image SIL3114 SATA driver support"
+	help
+	  Enable this driver to support the SIL3114 SATA controllers.
+
 endmenu