dm: exynos: gpio: Convert to driver model

Convert the exynos GPIO driver to driver model. This implements the generic
GPIO interface but not the extra Exynos-specific functions.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/configs/s5p_goni.h b/include/configs/s5p_goni.h
index 781d847..76b0503 100644
--- a/include/configs/s5p_goni.h
+++ b/include/configs/s5p_goni.h
@@ -289,5 +289,8 @@
 #define CONFIG_OF_LIBFDT
 
 #define CONFIG_SYS_GENERIC_BOARD
+#define CONFIG_DM
+#define CONFIG_CMD_DM
+#define CONFIG_DM_GPIO
 
 #endif	/* __CONFIG_H */