Rename GPIO_SUPPORT to GPIO

Rename these options so that CONFIG_IS_ENABLED can be used with them.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-imx/mx6/Kconfig b/arch/arm/mach-imx/mx6/Kconfig
index d5664a1..789a50d 100644
--- a/arch/arm/mach-imx/mx6/Kconfig
+++ b/arch/arm/mach-imx/mx6/Kconfig
@@ -301,7 +301,7 @@
 	select PINCTRL
 	select SPL
 	select SPL_DM if SPL
-	select SPL_GPIO_SUPPORT if SPL
+	select SPL_GPIO if SPL
 	select SPL_LIBCOMMON_SUPPORT if SPL
 	select SPL_LIBDISK_SUPPORT if SPL
 	select SPL_LIBGENERIC_SUPPORT if SPL