pinctrl: pinctrl-adi2: Add dependency to arch BLACKFIN in Kconfig.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
index f45a21c..21db201 100644
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -51,6 +51,7 @@
 
 config PINCTRL_ADI2
 	bool "ADI pin controller driver"
+	depends on BLACKFIN
 	select PINMUX
 	select IRQ_DOMAIN
 	help