bnxt_en: Validate vlan protocol ID on RX packets

Only pass supported VLAN protocol IDs for stripped VLAN tags to the
stack.  The stack will hit WARN() if the protocol ID is unsupported.

Existing firmware sets up the chip to strip 0x8100, 0x88a8, 0x9100.
Only the 1st two protocols are supported by the kernel.

Fixes: a196e96b

 ("bnxt_en: clean up VLAN feature bit handling")
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>