The vref_mode_dq, vref_value_dq on lpddr4 value is depending on IO settings of rd_vref. Add support for it. Signed-off-by: Jagan Teki <jagan@amarulasolutions.com> Signed-off-by: YouMin Chen <cym@rock-chips.com> Reviewed-by: Kever Yang <Kever.yang@rock-chips.com>