samples: drivers: mbox: sample.drivers.mbox.nrf54h20_vevif and sample.drivers.mbox.nrf54h20_bellboard fails at nrf54h20

[Piotr Kosycarz]

Describe the bug
The samples/drivers/mbox/sample.drivers.mbox.nrf54h20_vevif and samples/drivers/mbox/sample.drivers.mbox.nrf54h20_bellboard

Observed for

• nrf54h20dk/nrf54h20/cpuapp

To Reproduce
Steps to reproduce the behavior:

1. have nrf54h20dk/nrf54h20/cpuapp connected
2. go to your zephyr dir
3. call ./scripts/twister -T samples/drivers/mbox -p nrf54h20dk/nrf54h20/cpuapp--device-testing --device-serial /dev/ttyACM0 -v --inline-logs
4. See console output with error

Expected behavior
Valid console output

Impact
Not clear

Logs and console output

*** Booting Zephyr OS build v3.6.0-3753-gbe682e22e166 ***
Hello from APP

Missing:

Pong (on channel 0)
Ping (on channel 1)

Environment (please complete the following information):

• OS: Ubuntu 20.04.1 LTS
• Toolchain Zephyr SDK 0.16.5
• Commit SHA or Version used: v3.6.0-3753-gbe682e22e166