Bluetooth: Fix device_found event length for remote name resolving

The correct length of the event is the size of the ev struct (not size
of the pointer like the code was previously using) plus the length of
the variable-sized EIR data at the end of the struct.

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