net: aquantia: add ethertype and PCP to rx flow filters

L2 EtherType filters allows to filter packet by EtherType field or
both EtherType and User Priority (PCP) field of 802.1Q.
UserPriority (vlan) parameter must be accompanied by mask 0x1FFF. That
is to distinguish VLAN filter from L2 Ethertype filter with
UserPriority since both User Priority and VLAN ID are passed in the
same 'vlan' parameter.

Example:
To add a filter that directs IP4 packess of priority 3 to queue 3:
ethtool -N <ethX> flow-type ether proto 0x800 vlan 0x600 m 0x1FFF \
action 3 loc 16

Signed-off-by: Dmitry Bogdanov <dmitry.bogdanov@aquantia.com>
Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>