arm64: dts: rockchip: remove vdd_log from rk3399-puma

vdd_log has no consumer and therefore will not be set to a specific
voltage. Still the PWM output pin gets configured and thence the vdd_log
output voltage will changed from it's default. Depending on the idle
state of the PWM this will slightly over or undervoltage the logic supply
of the RK3399 and cause instability with GbE (undervoltage) and PCIe
(overvoltage). Since the default value set by a voltage divider is the
correct supply voltage and we don't need to change it during runtime we
remove the rail from the devicetree completely so the PWM pin will not
be configured.

Signed-off-by: Klaus Goger <klaus.goger@theobroma-systems.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>