boards: nrf52_bsim: Replace irq name table with function call

The interrupt names are now defined in the HW models.
As a result, all source files in the nrf52_bsim folder are now
free of nrf52832 specific references. Therefore these can in
theory be used for other models as well.

Signed-off-by: Rubin Gerritsen <rubin.gerritsen@nordicsemi.no>