util/lint: Ignore "visible if" statement in Kconfig files

They allow reducing the visible set of options to remove clutter.

Change-Id: I18c953c7feae23c0752392a2bf8f49783c17310e
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/28635
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>

util/lint/kconfig_lint

@@ -682,6 +682,13 @@ sub build_and_parse_kconfig_tree {
             push( @inside_menu, $menu );
         }
 
+        # visible if <expr>
+        elsif ( $line =~ /^\s*visible if.*$/ ) {
+	    # Must come directly after menu line (and on a separate line)
+	    # but kconfig already checks for that.
+	    # Ignore it.
+        }
+
         # endmenu
         elsif ( $line =~ /^\s*endmenu/ ) {
             $inside_config = "";