Bluetooth: hci_sync: Convert MGMT_OP_GET_CONN_INFO

Synchronous version of MGMT_OP_GET_CONN_INFO

Implements:
  hci_read_rssi_sync
  hci_read_tx_power_sync

Signed-off-by: Brian Gix <brian.gix@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>