checkpatch: fix "Use of uninitialized value" warnings

checkpatch is currently confused about some complex macros and references
undefined variables $stat and $cond.

Make sure these are defined before using them.

Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Gerhard Sittig <gsi@denx.de>
Acked-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>