checkpatch: allow long lines containing URL

Allow lines with URL to exceed the 80 char limit for improved interaction
in adaption to ongoing but undocumented practice.

  $ git grep -E '://\S{77}.*' -- '*.[ch]'

As per RFC3986 [1], the URL format allows for alphanum, +, - and .
characters in the scheme before the separator :// as long as it starts
with a letter (e.g.  https, git, f.-+).

Recognition of URIs without more context information is prone to false
positives and thus currently left out of the heuristics.

$rawline is used in the check as comments are removed from $line.

[1] https://tools.ietf.org/html/rfc3986#section-3.1

Link: http://lkml.kernel.org/r/1511355432.12667.15.camel@elementarea.net


Signed-off-by: Andreas Brauchli <andreas.brauchli@sensirion.com>
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>