ram: rk3399: Compute stride for 1 channel a

Add stride computation for the sdram which support
single channel a

This configuration available in NanoPi NEO4 and the
same can work with existing rk3399-sdram-ddr3-1866.dtsi

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