platform: cznic: turris-omnia-mcu: Add support for MCU provided TRNG

Add support for true random number generator provided by the MCU.
New Omnia boards come without the Atmel SHA204-A chip. Instead the
crypto functionality is provided by new microcontroller, which has
a TRNG peripheral.

Signed-off-by: Marek Behún <kabel@kernel.org>
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Link: https://lore.kernel.org/r/20240701113010.16447-7-kabel@kernel.org


Signed-off-by: Arnd Bergmann <arnd@arndb.de>