ARM: dts: bcm283x: Add missing properties to the PWR LED

This adds the missing properties to the PWR LED for the RPi 3 & 4 boards,
which are already set for the other boards. Without them we will lose
the LED state after suspend.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>