siemens,am33x: add ubi fastmap support

From: Samuel Egli <samuel.egli@siemens.com>

Signed-off-by: Heiko Schocher <hs@denx.de>

include/configs/siemens-am33x-common.h

@@ -288,6 +288,8 @@
 #define CONFIG_LZO
 #define CONFIG_CMD_UBI
 #define CONFIG_CMD_UBIFS
+#define CONFIG_MTD_UBI_FASTMAP
+#define CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT      1
 #endif
 
 /* Commen environment */