USB: driver for mcs7830 (aka DeLOCK) USB ethernet adapter

This driver adds support for the DeLOCK USB ethernet adapter
and potentially others based on the MosChip MCS7830 chip.

It is based on the usbnet and asix drivers as well as the
original device driver provided by MosChip, which in turn
was based on the usbnet driver.

It has been tested successfully on an OHCI, but interestingly
there seems to be a problem with the mcs7830 when connected to
the ICH6/EHCI in my thinkpad: it keeps receiving lots of
broken packets in the RX interrupt. The problem goes away when
I'm using an active USB hub, so I assume it's not related to
the device driver, but rather to the hardware.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>