checkpatch.pl: check for the FSF mailing address

Kernel maintainers reject new instances of the GPL boilerplate paragraph
directing people to write to the FSF for a copy of the GPL, since the FSF
has moved in the past and may do so again.

Make this an error for new code, but just a --strict CHK in --file mode;
anyone interested in doing tree-wide cleanups of this form can enable this
test explicitly.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Git-commit: 4783f894d0f3bfb107cf3b1d9aed1f1a0672ee1d
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>