New network drivers for the Kyu operating system

This work is starting with the Allwinner H5, but the Xilinx Zynq should follow close behind

• upcoming network drivers
• H5 emac Phy interface
• structure of the H5 emac driver
• give it a try!
• pointers are 8 byte objects!
• peek at the U-boot sources
• a look at the U-boot Phy.c driver
• weak functions
• U-boot and MDIO
• the U-boot MDIO command
• DM -- the U-boot driver model