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.
[hci] Expose ifcommon_exec() in a local header so wireless commands can use it
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>