Bluetooth: Controller: Align DDPI usage with nRF54L power domains

Align DDPI usage with nRF54L series power domains and
available DDPI configurations.

Use indices below 4 when needing to bridge with GPIO,
use indices below 8 when needing to bridge with MCU domain
like CCM and AAR; and use indices above 7 to bridge with
Peripheral domain.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>