ieee802154: || vs && in ieee802154_is_valid_extended_addr()

The ieee802154_is_valid_extended_addr() always returns true because
there is a typo.  The || should be &&.  Neither 0x0000000000000000ULL
nor 0xffffffffffffffffULL are valid addresses.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>