jfs: don't walk off the end of ealist

commit d0fa70aca54c8643248e89061da23752506ec0d4 upstream.

Add a check before visiting the members of ea to
make sure each ea stays within the ealist.

Signed-off-by: lei lu <llfamsec@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>