[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/recovery.h b/fs/gfs2/recovery.h
index 1b35516..961feed 100644
--- a/fs/gfs2/recovery.h
+++ b/fs/gfs2/recovery.h
@@ -10,6 +10,8 @@
 #ifndef __RECOVERY_DOT_H__
 #define __RECOVERY_DOT_H__
 
+#include "incore.h"
+
 static inline void gfs2_replay_incr_blk(struct gfs2_sbd *sdp, unsigned int *blk)
 {
 	if (++*blk == sdp->sd_jdesc->jd_blocks)