net: mvpp2.c: Enable 10G support for port 0 (SFI)

net: mvpp2.c: Enable 10G support for port 0 (SFI)

This patch fixes some remaining issues in the mvpp2 driver for the 10GB
support on port 0. These changes are:

- Incorrect PCS configuration
- Skip PHY configuration when no PHY is connected
- Skip GMAC configurations if 10G SFI mode set

Signed-off-by: Stefan Chulski <[email protected]>
Signed-off-by: Stefan Roese <[email protected]>
Cc: Kostya Porotchkin <[email protected]>
Cc: Nadav Haklai <[email protected]>
Cc: Joe Hershberger <[email protected]>
Acked-by: Joe Hershberger <[email protected]>