rockchip: rk3399-puma: Restore correct VDD_LOG supply.

A commit from last year re-imported the DTS files form the upstream kernel.
By doing so the VDD_LOG regulator in the board's DTS was dropped.
Let's restore this, but move it into the u-boot overlay to prevent this
issue in the future.

Fixes: 167efc2c ("arm64: dts: rk3399: Sync v5.7-rc1 from Linux")
Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>