arm64: dts: clearfog-gt-8k: fix switch link configuration

The commit below caused a regression for clearfog-gt-8k, where the link
between the switch and the host does not come up.

Investigation revealed two issues:
- MV88E6xxx DSA no longer allows an in-band link to come up as the link
  is programmed to be forced down. Commit "net: dsa: mv88e6xxx: fix
  in-band AN link establishment" addresses this.

- The dts configured dissimilar link modes at each end of the host to
  switch link; the host was configured using a fixed link (so has no
  in-band status) and the switch was configured to expect in-band
  status.

With both issues fixed, the regression is resolved.

Fixes: 34b5e6a3

 ("net: dsa: mv88e6xxx: Configure MAC when using fixed link")
Reported-by: Martin Rowe <martin.p.rowe@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>