fdt_support: Don't panic if stdout alias is missing

Currently, using fdt_fixup_stdout() on a device tree that is missing
the relevant alias results in this:

WARNING: could not set linux,stdout-path FDT_ERR_NOTFOUND.
ERROR: /chosen node create failed
 - must RESET the board to recover.

FDT creation failed! hanging...### ERROR ### Please RESET the board ###

There is no reason for this to be a fatal error rather than a warning,
and removing this allows for a smooth transition on a platform where
the device tree currently lacks the correct aliases but will have them
in the future.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: York Sun <yorksun@freescale.com>

common/fdt_support.c

@@ -158,25 +158,30 @@ static int fdt_fixup_stdout(void *fdt, int chosenoff)
 	aliasoff = fdt_path_offset(fdt, "/aliases");
 	if (aliasoff < 0) {
 		err = aliasoff;
-		goto error;
+		goto noalias;
 	}
 
 	path = fdt_getprop(fdt, aliasoff, sername, &len);
 	if (!path) {
 		err = len;
-		goto error;
+		goto noalias;
 	}
 
 	/* fdt_setprop may break "path" so we copy it to tmp buffer */
 	memcpy(tmp, path, len);
 
 	err = fdt_setprop(fdt, chosenoff, "linux,stdout-path", tmp, len);
-error:
 	if (err < 0)
 		printf("WARNING: could not set linux,stdout-path %s.\n",
 		       fdt_strerror(err));
 
 	return err;
+
+noalias:
+	printf("WARNING: %s: could not read %s alias: %s\n",
+	       __func__, sername, fdt_strerror(err));
+
+	return 0;
 }
 #else
 static int fdt_fixup_stdout(void *fdt, int chosenoff)