net: phy: decouple PHY id and PHY address in fixed PHY driver

net: phy: decouple PHY id and PHY address in fixed PHY driver

Until now, the fixed_phy_add() function was taking as argument
'phy_id', which was used both as the PHY address on the fake fixed
MDIO bus, and as the PHY id, as available in the MII_PHYSID1 and
MII_PHYSID2 registers. However, those two informations are completely
unrelated.

This patch decouples them. The PHY id of fixed PHYs is hardcoded to be
0x0. Ideally, a really reserved value would be nicer, but there
doesn't seem to be an easy of making sure a dummy value can be
assigned to the Linux kernel for such usage.

The PHY address remains passed by the caller of phy_fixed_add().

Signed-off-by: Thomas Petazzoni <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Tested-by: Florian Fainelli <[email protected]>
Signed-off-by: David S. Miller <[email protected]>