dm: exynos: config: Use driver model for SPI flash

Use driver model for exynos5 board SPI flash.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>

include/configs/exynos-common.h

@@ -22,6 +22,7 @@
 #define CONFIG_DM_GPIO
 #define CONFIG_DM_SERIAL
 #define CONFIG_DM_SPI
+#define CONFIG_DM_SPI_FLASH
 
 #define CONFIG_ARCH_CPU_INIT
 #define CONFIG_DISPLAY_CPUINFO