ethernet: Add helper for assigning packet type when dest address does not match device address

Enable reuse of logic in eth_type_trans for determining packet type.

Suggested-by: Sabrina Dubroca <sd@queasysnail.net>
Cc: stable@vger.kernel.org
Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://lore.kernel.org/r/20240423181319.115860-3-rrameshbabu@nvidia.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>