ahci: st: Only build for ST-Micro h/w

This device is designed specifically to run on ST-Microelectronics'
hardware. To ensure no attempts are made to run on anything incompatible
we add a dependency on ST architecture

Suggested-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index d2209e4..4c338b2 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -100,6 +100,7 @@
 config AHCI_ST
 	tristate "ST AHCI SATA support"
 	depends on SATA_AHCI_PLATFORM
+	depends on ARCH_STI
 	help
 	  This option enables support for ST AHCI SATA controller.