[JFFS2] Revert Artem's Bunkage in debug messages.

Random unthinking 'cleanup' caused debug messages like this:
   Obsoleting node at 0x0006daf4 of len 0x3a4: <7>Dirtying

If messages are continuation of an existing line, they don't need
to be prefixed with KERN_DEBUG.

THINK. Or you will be replaced by a small shell script.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>