pegasus usb-net: Fix endianness bugs

This fixes various endianness bugs. Some harmless and some real ones.
This is tested on a PowerPC-64 machine.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Cc: Stable <stable@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>