HOWTO: add Japanese translation of Documentation/HOWTO

Add the japanese translation of the Documentation/HOWTO file.
Signed-off-by: Tsugikazu Shibata <tshibata@ab.jp.nec.com>
Cc: IKEDA Munehiro <m-ikeda@ds.jp.nec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>