ColdFire: Fix board.c warning message

Implicit declaration of nand_init() warning message

Signed-off-by: TsiChung Liew <Tsi-Chung.Liew@freescale.com>
diff --git a/lib_m68k/board.c b/lib_m68k/board.c
index e59c6b0..4fee35a 100644
--- a/lib_m68k/board.c
+++ b/lib_m68k/board.c
@@ -63,6 +63,8 @@
 #include <spi.h>
 #endif
 
+#include <nand.h>
+
 DECLARE_GLOBAL_DATA_PTR;
 
 static char *failed = "*** failed ***\n";