net: stmmac: Add support for U32 TC filter using Flexible RX Parser

This adds support for U32 filter by using an HW only feature called
Flexible RX Parser. This allow us to match any given packet field with a
pattern and accept/reject or even route the packet to a specific DMA
channel.

Right now we only support acception or rejection of frame and we only
support simple rules. Though, the Parser has the flexibility of jumping to
specific rules as an if condition so complex rules can be established.

This is only supported in GMAC5.10+.

The following commands can be used to test this code:

	1) Setup an ingress qdisk:
	# tc qdisc add dev eth0 handle ffff: ingress

	2) Setup a filter (e.g. filter by IP):
	# tc filter add dev eth0 parent ffff: protocol ip u32 match ip \
		src 192.168.0.3 skip_sw action drop

In every tests performed we always used the "skip_sw" flag to make sure
only the RX Parser was involved.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: Vitor Soares <soares@synopsys.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>