gpio: Add run-time dependencies to R-Car driver

The Renesas R-Car GPIO driver is only useful on shmobile unless build
testing.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Magnus Damm <damm@opensource.se>
Cc: Alexandre Courbot <gnurou@gmail.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -268,7 +268,7 @@ config GPIO_PXA
 
 config GPIO_RCAR
 	tristate "Renesas R-Car GPIO"
-	depends on ARM
+	depends on ARM && (ARCH_SHMOBILE || COMPILE_TEST)
 	help
 	  Say yes here to support GPIO on Renesas R-Car SoCs.