idpf: fix kernel panic on unknown packet types

In the very rare case where a packet type is unknown to the driver,
idpf_rx_process_skb_fields would return early without calling
eth_type_trans to set the skb protocol / the network layer handler.
This is especially problematic if tcpdump is running when such a
packet is received, i.e. it would cause a kernel panic.

Instead, call eth_type_trans for every single packet, even when
the packet type is unknown.

Fixes: 3a8845af ("idpf: add RX splitq napi poll support")
Reported-by: Balazs Nemeth <bnemeth@redhat.com>
Signed-off-by: Joshua Hay <joshua.a.hay@intel.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Tested-by: Salvatore Daniele <sdaniele@redhat.com>
Signed-off-by: Pavan Kumar Linga <pavan.kumar.linga@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>