net: phylink: Adjust link settings based on rate matching

If the phy is configured to use pause-based rate matching, ensure that
the link is full duplex with pause frame reception enabled. As
suggested, if pause-based rate matching is enabled by the phy, then
pause reception is unconditionally enabled.

The interface duplex is determined based on the rate matching type.
When rate matching is enabled, so is the speed. We assume the maximum
interface speed is used. This is only relevant for MLO_AN_PHY. For
MLO_AN_INBAND, the MAC/PCS's view of the interface speed will be used.

Although there are no RATE_ADAPT_CRS phys in-tree, it has been added for
comparison (and the implementation is quite simple).

Co-developed-by: Russell King <linux@armlinux.org.uk>
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>