warp7: Print secure/non-secure mode info

warp7 has two targets:

- warp7_defconfig: boots in non-secure mode
- warp7_secure_defconfig: boots in secure mode

Print the mode that is being used to help users to easily identify
which target is running on the board.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>

board/warp7/warp7.c

@@ -152,7 +152,14 @@ int board_init(void)
 
 int checkboard(void)
 {
-	puts("Board: WARP7\n");
+	char *mode;
+
+	if (IS_ENABLED(CONFIG_ARMV7_BOOT_SEC_DEFAULT))
+		mode = "secure";
+	else
+		mode = "non-secure";
+
+	printf("Board: WARP7 in %s mode\n", mode);
 
 	return 0;
 }