checkpatch: check for spin_is_locked()

checkpatch: check for spin_is_locked()

spin_is_locked() is usually misued. In checkpatch.pl:

- warn when it is used at all

- error out when it is asserted on free, because that's usually broken
  (e.g.  doesn't work on on uni processor builds).  Recommend
  lockdep_assert_held() instead.

[joe@perches.com: some improvements]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>