function prefix "undinet_" and the variable name "undinic" in undinet.c,
so that we can reserve the variable name "undi" for a struct undi_device.
The idea is that we preserve the Etherboot 5.4 convention that the "UNDI"
code refers to our using an underlying UNDI stack, while the "PXE" code
refers to our providing a PXE API.
UNDI_GET_INFORMATION calls into drivers/net/undi.c. undi_probe() now
gets given a pxe_device representing a PXE stack that has been loaded
into memory but not initialised in any way.
I want to get to the point where any header in include/ reflects a
standard user-level header (e.g. a POSIX header), while everything that's
specific to gPXE lives in include/gpxe/. Headers that reflect a Linux
header (e.g. if_ether.h) should also be in include/gpxe/, with the same
name as the Linux header and, preferably, the same names used for the
definitions.
