rockchip: rk3399-puma: Set VDD_LOG to 950 mV.

This patch sets VDD_LOG to 950 mV on RK3399-Q7.
This is required to address stability issues on Puma
in heavy-load use-cases.

Reported-by: Assaf Agmon <assaf@r-go.io>
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>