ipq40xx: 5.4: fix ethernet driver

ipq40xx: 5.4: fix ethernet driver

In 5.4 kernel old u32 array way of setting network features was dropped and linkmode is now the only way.
So lets migrate the EDMA driver to support linkmode.
Also, old get/set settings API for ethtool is also dropped so lets convert to new ksettings API while at it as it demands linkmode.

Now, gigabit works properly as well as ethtool.
Previously you would get this in ethtool:
root@OpenWrt:/# ethtool eth1
Settings for eth1:
        Supports Wake-on: d
        Wake-on: d
        Current message level: 0x00000000 (0)

        Link detected: yes

Now, features are properly advertised:
root@OpenWrt:/# ethtool eth1
Settings for eth1:
        Supported ports: [ TP MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Half 1000baseT/Full
        Supported pause frame use: Symmetric Receive-only
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Half 1000baseT/Full
        Advertised pause frame use: Symmetric Receive-only
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Link partner advertised link modes:  10baseT/Half 10baseT/Full
                                             100baseT/Half 100baseT/Full
                                             1000baseT/Full
        Link partner advertised pause frame use: No
        Link partner advertised auto-negotiation: No
        Link partner advertised FEC modes: Not reported
        Speed: 1000Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 4
        Transceiver: internal
        Auto-negotiation: on
        MDI-X: Unknown
        Supports Wake-on: d
        Wake-on: d
        Current message level: 0x00000000 (0)

        Link detected: yes

Signed-off-by: Robert Marko <robert.marko@sartura.hr>