Changeset 51450d7 in rtems for c/src/lib/libbsp/i386/pc386

Added NE2000 Driver from Ian Lance Taylor <ian@…>. Comments:

Both the ne2000 and the wd80x3 are based on the National Semiconductor
8390 chip, so there is a fair amount of overlap between the two
drivers. It would be possible in principle to combine some code into
a separate set of subroutines called by both. In fact, the drivers in
both OpenBSD and Linux work this way. I didn't bother, because for
the relatively simple drivers used by RTEMS, the overlap is not
especially large, and any reasonable use of subroutines would lead to
slightly less efficient code.

This ne2000 driver uses two transmit buffers. While one packet is
being transmitted over the Ethernet, RTEMS will upload another. Since
uploading a packet to the ne2000 is rather slow, I don't think there
is any point to having more than two transmit buffers. However, the
code does make it possible, by changing NE_TX_BUFS, although that
would of course reduce the number of receive buffers.

I suspect that the wd80x3 driver would benefit slightly from copying
the multiple transmit buffer code. However, I have no way to test
that.