soc: nordic: nRF54L: Move a few options from boards to the SoC definition

A few option defaults that were so far defined in the board _defconfig
files are actually entirely SoC family (nRF54L) dependant, so it makes
much more sense to have them defined at the SoC family level in order
for all boards based on these SoCs to automatically inherit them.

Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>