net: ravb: Filter out supported PHY features

The RAVB only supports 100Full and 1000Full operation, it does not support
10Full or any Half-duplex modes. The PHY could still advertise those features
though, so filter out the PHY features accordingly.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Cc: Joe Hershberger <joe.hershberger@ni.com>