modules: Kconfig: Make options enabling nrfx drivers easier to access

The options are given prompts, so that they become accessible from
application configuration files and visible in menuconfig, and they
are complemented with proper dependencies, so that only the relevant
ones for the selected SoC are made available.

Jira: NCSDK-2744

Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>