gpio: Rename devres implementation file

All the other core files are named "gpiolib-<something>" so
let's rename the devres as well so we have some logical
namespacing here.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Makefile

@@ -3,8 +3,8 @@
 
 ccflags-$(CONFIG_DEBUG_GPIO)	+= -DDEBUG
 
-obj-$(CONFIG_GPIOLIB)		+= devres.o
 obj-$(CONFIG_GPIOLIB)		+= gpiolib.o
+obj-$(CONFIG_GPIOLIB)		+= gpiolib-devres.o
 obj-$(CONFIG_GPIOLIB)		+= gpiolib-legacy.o
 obj-$(CONFIG_GPIOLIB)		+= gpiolib-devprop.o
 obj-$(CONFIG_OF_GPIO)		+= gpiolib-of.o