Prevent crash if random DTB address is passed to bootm

This patch adds bootm_start() return value check. If
error status is returned, we do not proceed further to
prevent board reset or crash as we still can recover
at this point.

Signed-off-by: Anatolij Gustschin <agust@denx.de>

common/cmd_bootm.c

@@ -361,7 +361,8 @@ int do_bootm (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 	ulong		load_end = 0;
 	int		ret;
 
-	bootm_start(cmdtp, flag, argc, argv);
+	if (bootm_start(cmdtp, flag, argc, argv))
+		return 1;
 
 	/*
 	 * We have reached the point of no return: we are going to

common/image.c

@@ -1516,7 +1516,7 @@ int boot_get_fdt (int flag, int argc, char *argv[], bootm_headers_t *images,
 			}
 			break;
 		default:
-			fdt_error ("Did not find a cmdline Flattened Device Tree");
+			puts ("ERROR: Did not find a cmdline Flattened Device Tree\n");
 			goto error;
 		}