RK3399 EVB use 2 SYR837/8 and a RK808 for power supply,
Add regulator tree for it.
Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Link: https://lore.kernel.org/r/20200305113912.32226-3-andy.yan@rock-chips.comSigned-off-by: Heiko Stuebner <heiko@sntech.de>