Change some filenames to make pinmuxing experimenting easier.

By using xxx_cyclone5 names the file names correspond to what the Altera generator spits out.

Signed-off-by: Charles Manning <cdhmanning@gmail.com>
Fix MAC address reading

Using a different EEPROM, so fix up address and address size.

The part we're using has 256 bytes. The MAC address is in the last
6 bytes.

Signed-off-by: Charles Manning <cdhmanning@gmail.com>