Bluetooth: Add tracking of local and piconet clock values

This patch adds support for storing the local and piconet clock values
from the HCI_Read_Clock command response to the hci_dev and hci_conn
structs. This will be later used in another patch to implement support
for the Get Clock Info mgmt command.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>