gfs2: Minor gfs2_lookup_by_inum cleanup

Use a zero no_formal_ino instead of a NULL pointer to indicate that any inode
generation number will qualify: a valid inode never has a zero no_formal_ino.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h
index 580adbf..b52ecf4 100644
--- a/fs/gfs2/inode.h
+++ b/fs/gfs2/inode.h
@@ -92,7 +92,7 @@ extern struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned type,
 				       u64 no_addr, u64 no_formal_ino,
 				       unsigned int blktype);
 extern struct inode *gfs2_lookup_by_inum(struct gfs2_sbd *sdp, u64 no_addr,
-					 u64 *no_formal_ino,
+					 u64 no_formal_ino,
 					 unsigned int blktype);
 
 extern int gfs2_inode_refresh(struct gfs2_inode *ip);