or1k: dts: Fix ethoc network configuration in or1ksim devicetree

This fixes several issues with the ethoc network device config.

Fisrt off, the compatible property used an obsolete compatibility
string; this caused the initialization to be skipped.  Next, the
register map was not given enough space to allocate ring descriptors,
this caused module initialization to abort.  Finally, we need to mark
this device as big-endian as needed by openrisc.

This was tested by me in qemu, the setup is documented on the qemu wiki:

  https://wiki.qemu.org/Documentation/Platforms/OpenRISC



Signed-off-by: Stafford Horne <shorne@gmail.com>