Many lines of code extend beyond the maximum line length.  Some of these
are possibly justified by use type.

For instance:

structure definitions where comments are added per member like:
struct foo {
	type member;		/* some long description */

And lines that don't fit the typical logging message style
where a string constant is used like:

        SOME_MACRO(args, "Some long string");

Categorize these long line types so that checkpatch can use a command-line
--ignore=<type> option to avoid emitting some long line warnings.

One of the existing checkpatch exclusions allowed kernel-doc argument
documentation to exceed 80 columns because old versions of kernel-doc
required single line documentation.  The requirement was removed in 2009
so remove that exclusion.

Add documentation to make the test a bit clearer.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Michael Shuey <shuey@purdue.edu>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>