GFS2: Move i_size from gfs2_dinode_host and rename it to i_disksize

This patch moved the i_size field from the gfs2_dinode_host and
following the ext3 convention renames it i_disksize.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c
index fcfaaef..d7e649e 100644
--- a/fs/gfs2/ops_file.c
+++ b/fs/gfs2/ops_file.c
@@ -478,7 +478,7 @@
 			goto fail;
 
 		if (!(file->f_flags & O_LARGEFILE) &&
-		    ip->i_di.di_size > MAX_NON_LFS) {
+		    ip->i_disksize > MAX_NON_LFS) {
 			error = -EOVERFLOW;
 			goto fail_gunlock;
 		}