doc boards nrfbsim: Update list of supported HW

The models include enough of the CRACEN to run the same
nrfx drivers as in Zephyr. So let's add it to the list.

Also let's remove the RTC from the list as the hal does not
expose it anymore for this platform as the GRTC is to be used
instead.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>