tc35815 driver update (take 2)

Current tc35815 driver is very obsolete and less maintained for a long
time.  Replace it with a new driver based on one from CELF patch
archive.

Major advantages of CELF version (version 1.23, for kernel 2.6.10) are:

* Independent of JMR3927.
  (Actually independent of MIPS, but AFAIK the chip is used only on
   MIPS platforms)
* TX4938 support.
* 64-bit proof.
* Asynchronous and on-demand auto negotiation.
* High performance on non-coherent architecture.
* ethtool support.
* Many bugfixes and cleanups.

And improvoments since version 1.23 are:

* TX4939 support.
* NETPOLL support.
* NAPI support. (disabled by default)
* Reduce memcpy on receiving.
* PM support.
* Many cleanups and bugfixes.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Jeff Garzik <jeff@garzik.org>