Documentation/SubmittingPatches: Reported-by tags and permission

The reported-by text says you have to ask for permission, but that
should only be if the bug was reported in private.  These days the
standard is to always give reported-by credit or it's considered a bit
rude.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>