dm: exynos: Move s5p_goni to generic board

The generic board deadline is approaching, and we need this feature to
enable driver model. Enable CONFIG_SYS_GENERIC_BOARD for s5p_goni.
Signed-off-by: NSimon Glass <sjg@chromium.org>

include/configs/s5p_goni.h

@@ -288,4 +288,6 @@
 
 #define CONFIG_OF_LIBFDT
 
+#define CONFIG_SYS_GENERIC_BOARD
+
 #endif	/* __CONFIG_H */