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-tegra/Kconfig b/arch/arm/mach-tegra/Kconfig
index a397748..478c7a9 100644
--- a/arch/arm/mach-tegra/Kconfig
+++ b/arch/arm/mach-tegra/Kconfig
@@ -1,6 +1,6 @@
 if ARCH_TEGRA
 
-config SPL_GPIO_SUPPORT
+config SPL_GPIO
 	default y
 
 config SPL_LIBCOMMON_SUPPORT