ADS5121e: fix compile warning

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/board/ads5121/ads5121.c b/board/ads5121/ads5121.c
index 46be6a5..8531657 100644
--- a/board/ads5121/ads5121.c
+++ b/board/ads5121/ads5121.c
@@ -25,6 +25,7 @@
 #include <mpc512x.h>
 #include <asm/bitops.h>
 #include <command.h>
+#include <fdt_support.h>
 
 /* Clocks in use */
 #define SCCR1_CLOCKS_EN	(CLOCK_SCCR1_CFG_EN |				\