Michael Brown
faf50e8fa3
[pxe] Check for a valid PXE network device when applicable
Very nasty things can happen if a NULL network device is used. Check
that pxe_netdev is non-NULL at the applicable entry points, so that
this type of problem gets reported to the caller rather than being
allowed to crash the system.
Signed-off-by: Michael Brown <mcb30@ipxe.org>