Bluetooth: Controller: Switch to Zephyr's hci.h for cmd handling

Continue using Zephyr's include/bluetooth/hci.h for HCI command
handling in more of the commands, including the informational ones.
This is the second commit in a series that transitions from
the structures in hci.c to the ones in hci.h.

Jira: ZEP-726

Change-Id: Iecbc7ae5ba2c8435a51d62d59e8095aa25e6dc0e
Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>