checkpatch: skip fdtdec_* check for tools

Have checkpatch.pl skip warnings for use of fdtdec_* functions in
ooling; livetree isn't used there.

Signed-off-by: Lars Feyaerts <lars@bitbiz.be>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 62b764f..488d73a 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2606,8 +2606,8 @@
 		     "Possible new uclass - make sure to add a sandbox driver, plus a test in test/dm/<name>.c\n" . $herecurr);
 	}
 
-	# try to get people to use the livetree API
-	if ($line =~ /^\+.*fdtdec_/) {
+	# try to get people to use the livetree API, except when changing tooling
+	if ($line =~ /^\+.*fdtdec_/ && $realfile !~ /^tools\//) {
 		WARN("LIVETREE",
 		     "Use the livetree API (dev_read_...)\n" . $herecurr);
 	}