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

scripts/checkpatch.pl

@@ -3198,20 +3198,12 @@ sub process {
 				$herecurr);
 		}
 
-# check for needless kfree() checks
-		if ($prevline =~ /\bif\s*\(([^\)]*)\)/) {
-			my $expr = $1;
-			if ($line =~ /\bkfree\(\Q$expr\E\);/) {
-				WARN("NEEDLESS_KFREE",
-				     "kfree(NULL) is safe this check is probably not required\n" . $hereprev);
-			}
-		}
-# check for needless usb_free_urb() checks
-		if ($prevline =~ /\bif\s*\(([^\)]*)\)/) {
-			my $expr = $1;
-			if ($line =~ /\busb_free_urb\(\Q$expr\E\);/) {
-				WARN("NEEDLESS_USB_FREE_URB",
-				     "usb_free_urb(NULL) is safe this check is probably not required\n" . $hereprev);
+# check for needless "if (<foo>) fn(<foo>)" uses
+		if ($prevline =~ /\bif\s*\(\s*($Lval)\s*\)/) {
+			my $expr = '\s*\(\s*' . quotemeta($1) . '\s*\)\s*;';
+			if ($line =~ /\b(kfree|usb_free_urb|debugfs_remove(?:_recursive)?)$expr/) {
+				WARN('NEEDLESS_IF',
+				     "$1(NULL) is safe this check is probably not required\n" . $hereprev);
 			}
 		}