net: mvpp2: cls: Use a bitfield to represent the flow_type

As of today, the classification code is used only for RSS. We split the
incoming traffic into multiple flows, that correspond to the ethtool
flow_type parameter.

We don't want to use the ethtool flow definitions such as TCP_V4_FLOW,
for several reason :

 - We want to decorrelate the driver code from ethtool as much as
   possible, so that we can easily use other interfaces such as tc flower,

 - We want the flow_type to be a bitfield, so that we can match flows
   embedded into each other, such as TCP4 which is a subset of IP4.

This commit does the conversion to the newer type.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>