add SubmittingPatches to Documentation/ja_JP

This patch adds SubmittingPatches translated into Japanese to 
Documentation/ja_JP directory.

I attach the patch because there is a possibility that MUA 
will change the character encoding sometimes.
Signed-off-by: Keiichi KII <k-keiichi@bx.jp.nec.com>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>