net: dsa: sja1105: Update some comments about PHYLIB

Since the driver is now using PHYLINK exclusively, it makes sense to
remove all references to it and replace them with PHYLINK.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>