versatile: board configs: Use buffered writes on flash

This patch provides a support to use buffered writes on flash
for versatile and vexpress boards.

This will certainly increase the flash writes.

Signed-off-by: Jagannadha Sutradharudu Teki <402jagan@gmail.com>
diff --git a/include/configs/ca9x4_ct_vxp.h b/include/configs/ca9x4_ct_vxp.h
index 312fd94..a7cd1d4 100644
--- a/include/configs/ca9x4_ct_vxp.h
+++ b/include/configs/ca9x4_ct_vxp.h
@@ -163,6 +163,8 @@
 /* Room required on the stack for the environment data */
 #define CONFIG_ENV_SIZE			FLASH_MAX_SECTOR_SIZE
 
+#define CONFIG_SYS_FLASH_USE_BUFFER_WRITE /* use buffered writes */
+
 /*
  * Amount of flash used for environment:
  * We don't know which end has the small erase blocks so we use the penultimate