net: phy: mscc: remove non-MACSec compatible phy

Selecting VSC8575 as a MACSec PHY was not correct

The relevant datasheet can be found here:
  - VSC8575: https://www.microchip.com/wwwproducts/en/VSC8575



History:
v1 -> v2:
   - Corrected the sha in the "Fixes:" tag

Fixes: 1bbe0ecc ("net: phy: mscc: macsec initialization")
Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
Reviewed-by: Antoine Tenart <atenart@kernel.org>
Link: https://lore.kernel.org/r/20201113091116.1102450-1-steen.hegelund@microchip.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>