gpiolib: make GPIO_DEVRES depend on GPIOLIB

Current Kconfig allows GPIO_DEVRES to be selected and compiled without
GPIOLIB. This does not make sense anymore since GPIOLIB has become the
exclusive way to deal with GPIOs. This patch makes GPIO_DEVRES available
only if GPIOLIB is selected.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 92e258c..62eb9ef 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -30,10 +30,6 @@
 	  Selecting this from the architecture code will cause the gpiolib
 	  code to always get built in.
 
-config GPIO_DEVRES
-	def_bool y
-	depends on HAS_IOMEM
-
 
 menuconfig GPIOLIB
 	bool "GPIO Support"
@@ -47,6 +43,10 @@
 
 if GPIOLIB
 
+config GPIO_DEVRES
+	def_bool y
+	depends on HAS_IOMEM
+
 config OF_GPIO
 	def_bool y
 	depends on OF