dts: nrf54h20: Add missing global dppic and ipcst configs

There were missing global dppic and ipct channels configuration
that allows to deliver events from global peripherlas like GRTC
to Radio domain.

Add missing configuration to nrf54h20 dtsi file.
Signed-off-by: Piotr Pryga <piotr.pryga@nordicsemi.no>