ram: rk3399: Update lpddr4 vref based on io settings

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>
1 file changed