checkpatch: consolidate if (foo) bar(foo) checks and add debugfs_remove

Consolidate the if (foo) bar(foo) detectors into a single check.  Add
debugfs_remove and family.

Based on a patch by Constantine Shulyupin.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
Cc: Constantine Shulyupin <const@MakeLinux.com>.
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>