Bluetooth: controller: nRF5x: refactor radio_nrf5_ppi.h

[kruithofa]

Is your enhancement proposal related to a problem? Please describe.
The conditional compilation makes the code more difficult to read/understand.
There is also inconsistency in the functionality for the routine 'hal_radio_switch_disable()', in radio_nrf5_ppi.h lines 454 vs. 1268

Describe the solution you'd like

• Split the nrf5_ppi.h in 2 files for improved readability
• Make the different routines consistent

Describe alternatives you've considered
[None]

Additional context
See PR #26019

[cvinayak]

Fixed in #30732