checkpatch: report the correct lines for single statement blocks

Report the correct lines for single statement blocks.  Currently we are
reporting the right number of lines, but not skipping the negative lines.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>