ocfs2: Remove obscure error handling in direct_write.

In ocfs2, actually we don't allow any direct write pass i_size,
see the function ocfs2_prepare_inode_for_write. So we don't
need the bogus simple_setsize.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>