net: ethernet: xilinx_emaclite: set protocol selector bits when writing ANAR

This patch sets the protocol selector bits (4:0) of the PHY's MII_ADVERTISE
register (ANAR) when writing ADVERTISE_ALL. The protocol selector bits are
indicating IEEE 803.3u support and are fixed / read-only on some PHYs. Not
setting them correctly on others (like TI DP83630) makes the PHY fall back
to 10M HDX mode which should be avoided.

Tested for TI DP83630 PHY on Microblaze platform.

Signed-off-by: Jens Renner <renner@efe-gmbh.de>
Tested-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>