arm: mvebu: dts: Fix Turris Mox device tree

arm: mvebu: dts: Fix Turris Mox device tree

DTC issues a warning because #address-cells and #size-cells properties
are not set in the mdio node.
Also add ethernet1 alias.
Also add RTC node.
Also fix USB3 regulator startup delay time.
Also fix PCI Express SERDES speed to 5 GHz (this is only cosmetic, the
speed value is not used byt the comphy driver for PCI Express, but
should be 5 GHz nonetheless).

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Stefan Roese <sr@denx.de>