Bluetooth: controller: Address nRF5340 Engineering A Errata 16

Address the nRF5340 Engineering A Errata 16, RADIO: POWER
register is not functional.

This affects the dependency of controller's HAL
implementation that expected correct reset values being
set in the Radio peripheral.

As the SUBSCRIBE_TXEN and SUBSCRIBE_RXEN where not in their
reset value, Radio transmission and reception start using
DPPI was broken.

Fixes #25942.

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