Relax port lint rule for patchfile naming

[Jan Stary]

While we're here:

> >> How will you distinguish patchfiles from others

> The lint check in question doesn't look at the contents of files/, it
> looks at the patchfiles option.

what e.g. OpenBSD does is it has a patches/ subdirectory in the port dir.
Anything in there is a patch to be applied. No extra keyword/option for it.
(files/ is extra files to be added to WRKSRC; no keyword for it).

I believe it is simpler to what MP has now:
patchfiles need to be declared such with 'patchfiles',
and extra files need to be created _in_ the Portfile
(as e.g. textproc/mandoc does for configure.local).

	Jan