[GFS2] Make headers compile on their own

As per Jan Engelhardt's comments, this should make all the headers
compile on their own by including and/or declaring structures
early.

Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/lops.h b/fs/gfs2/lops.h
index 2e3365c..5839c05 100644
--- a/fs/gfs2/lops.h
+++ b/fs/gfs2/lops.h
@@ -10,6 +10,9 @@
 #ifndef __LOPS_DOT_H__
 #define __LOPS_DOT_H__
 
+#include <linux/list.h>
+#include "incore.h"
+
 extern const struct gfs2_log_operations gfs2_glock_lops;
 extern const struct gfs2_log_operations gfs2_buf_lops;
 extern const struct gfs2_log_operations gfs2_revoke_lops;