board: constify struct node_info array

Add 'const' (also 'static' in some places) to struct node_info
arrays to save memory footprint.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/board/CarMediaLab/flea3/flea3.c b/board/CarMediaLab/flea3/flea3.c
index c0f33b8..9eec1b7 100644
--- a/board/CarMediaLab/flea3/flea3.c
+++ b/board/CarMediaLab/flea3/flea3.c
@@ -205,7 +205,7 @@
  */
 int ft_board_setup(void *blob, bd_t *bd)
 {
-	struct node_info nodes[] = {
+	static const struct node_info nodes[] = {
 		{ "physmap-flash.0", MTD_DEV_TYPE_NOR, },  /* NOR flash */
 		{ "mxc_nand", MTD_DEV_TYPE_NAND, }, /* NAND flash */
 	};