Corrected IRQ triggering and level settings according to latest revision
of the 440EP User Manual (rev 1.24 nov 16, 2007).

The incorrect settings might cause a failure of the network if both
onchip ethernet ports are under heavy load.
Signed-off-by: NWolfgang Ocker <weo@reccoware.de>
Acked-by: NStefan Roese <sr@denx.de>
Signed-off-by: NJosh Boyer <jwboyer@linux.vnet.ibm.com>