rockchip: dts: rk3399: Add LPDDR4-100 timings

Add sdram timings for LPDDR4-100 via rk3399-sdram-lpddr4-100.dtsi file.
all timings are dumped from rkbin/bin/rk33/rk3399_ddr_800MHz_v1.20.bin

Associated LPDDR4 board -u-boot.dtsi can include this to make these
timings available during SPL or TPL stages.

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>