ifcommon_exec() was long-ago marked as __attribute__((regparm(2))) in
order to minimise the size of functions that call into it.  Since
then, gPXE has added -mregparm=3 as a general compilation option, and
this "optimisation" is now counter-productive.

Change (and simplify) the prototype to minimise code size given the
current compilation conditions.

This keeps code size down, since the wireless interface management
commands have the same command-line interface and overall structure as
the wired commands.

Signed-off-by: Michael Brown <mcb30@etherboot.org>

Add FILE_LICENCE declarations to almost all files that make up the
various standard builds of gPXE.

bytes of useless zeroes in the final image.

by PXE and NBI) and UNDI packets (as used by undinet and UNDI).

UNDI stack.

typical build will now include 880 bytes of PCI support code, compared to
2327 bytes in Etherboot 5.4.

(There is a slight cost of around 5 extra bytes per access to a
non-constant config space address; this should be an overall win.
Driver-specific accesses will usually be to constant addresses, for
which there is no additional cost.)

Yes, you really can do it in 65 bytes.