ARM: dts: Cygnus: Fix MDIO node address/size cells

ARM: dts: Cygnus: Fix MDIO node address/size cells

BugLink: https://bugs.launchpad.net/bugs/1861929
[ Upstream commit fac2c2da3596d77c343988bb0d41a8c533b2e73c ]

The MDIO node on Cygnus had an reversed #address-cells and
 #size-cells properties, correct those.

Fixes: 40c26d3af60a ("ARM: dts: Cygnus: Add the ethernet switch and ethernet PHY")
Reported-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>