leaking_addresses: add SigIgn to false positives

Signal masks are false positives, we already check for SigBlk and SigCgt
but we missed SigIgn.

Add SigIgn to false positive check.

Signed-off-by: Tobin C. Harding <[email protected]>
diff --git a/scripts/leaking_addresses.pl b/scripts/leaking_addresses.pl
index 6efd1fd..bc57880 100755
--- a/scripts/leaking_addresses.pl
+++ b/scripts/leaking_addresses.pl
@@ -228,6 +228,7 @@
 
 	# Signal masks.
 	if ($line =~ '^SigBlk:' or
+	    $line =~ '^SigIgn:' or
 	    $line =~ '^SigCgt:') {
 		return 0;
 	}