Fix a typo in fw_env.config

Reported-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Wolfgang Denk <wd@denx.de>

tools/env/fw_env.config

 # Configuration file for fw_(printenv/saveenv) utility.
-# Up to two entries are valid, in this case the redundand
+# Up to two entries are valid, in this case the redundant
 # environment sector is assumed present.
 # Notice, that the "Number of sectors" is ignored on NOR.