net: korina: Make driver COMPILE_TESTable

Move structs/defines for ethernet/dma register into driver, since they
are only used for this driver and remove any MIPS specific includes.
This makes it possible to COMPILE_TEST the driver.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: David S. Miller <davem@davemloft.net>