Bluetooth: Read stored link key information when powering on controller

The information about max stored link keys and current stored link keys
should be read at controller initialization. So issue HCI Read Stored
Link Key command with BDADDR_ANY and read_all flag set to 0x01 to
retrieve this information.

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