staging: Remove test of is_broadcast with is_multicast

A broadcast packet is a multicast packet, no need to test twice.

Reorder one defective test in rtl_core of is_multi_ether_addr
before is_broadcast_ether_addr as the is_multi returns true for
broadcast frames.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>