Revert "checkpatch: close filp_open loophole."

This reverts commit 54678ad02c.

Change-Id: I14a32c6c446026769e3d27f0d04b10d0d141b27d
Signed-off-by: Hepson Sanchez <sanchez@codeaurora.org>

scripts/checkpatch.pl

@@ -5686,13 +5686,6 @@ sub process {
 			      $herecurr);
 		}
 
-# filp_open is a backdoor for sys_open
-		if ($line =~ /\b(filp_open)\b/) {
-			ERROR("FILE_OPS",
-			      "$1 is inappropriate in kernel code.\n" .
-			      $herecurr);
-		}
-
 # read[bwl] & write[bwl] use too many barriers, use the _relaxed variants
 		if ($line =~ /\b((?:read|write)[bwl])\b/) {
 			ERROR("NON_RELAXED_IO",