Bluetooth: Fix EIR data clearing when powering off

When powering off we should assume that the EIR data isn't valid
anymore. This patch makes sure it gets cleared in hci_dev_do_close and
thereby ensures that a correct new EIR is recreated when powering on
again.

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