bluetooth: controller: openisa: encryption and decryption using CAUv3

Created unit tests for the encryption and decryption functions.
Tested with the peripheral and with central_hr samples.
Due to latency of CAUv3 when used as CCM inline accelerator
only one of the PDU can be encrypted/decrypted within an
bilateral exchange M->S + S->M in a connection event.
If the RXed PDU is encrypted, the TXed PDU must be empty
with More Data if there is data in the LLL queue.
The TXed PDU will be encrypted when an empty PDU is RXed.

Signed-off-by: Cristi Caciuloiu <cristian.caciuloiu@nxp.com>