net: dsa: sja1105: register the MDIO buses for 100base-T1 and 100base-TX

The SJA1110 contains two types of integrated PHYs: one 100base-TX PHY
and multiple 100base-T1 PHYs.

The access procedure for the 100base-T1 PHYs is also different than it
is for the 100base-TX one. So we register 2 MDIO buses, one for the
base-TX and the other for the base-T1. Each bus has an OF node which is
a child of the "mdio" subnode of the switch, and they are recognized by
compatible string.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>