gitweb/README: remove reference to git.kernel.org
git.kernel.org no longer uses gitweb but has switched to cgit.
Info about this can be found on: https://www.kernel.org/pelican.html
or simply by looking at http://git.kernel.org . This is change since
2013-03-01.
Signed-off-by: Fredrik Gustafsson <iveqy@iveqy.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
authored by