ARM: uniphier: enable GPIO command and driver for UniPhier SoCs

This allows to use the "gpio" command.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index d8b63e9..94bd7ec 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -697,6 +697,7 @@
 	select SPL_OF_CONTROL
 	select DM
 	select SPL_DM
+	select DM_GPIO
 	select DM_SERIAL
 	select DM_I2C
 	help