As far as u-boot is concerned the ds1339 is compatible with the other
devices supported by the ds1307 driver. The Linux driver does expose
some additional functionality but as far as u-boot is concerned just
adding the compatible string is enough.
Signed-off-by: Chris Packham <judge.packham@gmail.com> Reviewed-by: Simon Glass <sjg@chromium.org> Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>