linux-topic: Ethernet fixup for final version

Use PHY ID 3 for the ethernet PHY and a GPIO interrupt instead of the GIC.
This matches the production boards.

Fix EMAC module name for autoload, xilinx_emacps instead of xilinx-emacps.
topic-miami: Enable secondary UART

Allow UART1 to be used via EMIO. It can for example be routed to the
FTDI chip on the Florida board for a high speed serial link.