odhcpd: remove confusing #defines

odhcpd: remove confusing #defines

Right now, odhcpd.h contains lines like "#define hwaddr mac", which is a great
footgun when hacking on odhcpd (like when creating a function with a local
variable named "hwaddr" and later getting compiler errors talking about how
"mac" has the wrong type...in a function which has no variable named "mac").

So, remove these definitions. I'm not sure the chosen variable names are the
most descriptive, but I erred on the side of caution and picked the alternative
that required the least amount of changes. We can always change the names of
the variables later.

Signed-off-by: David Härdeman <[email protected]>
Link: https://github.com/openwrt/odhcpd/pull/261
Signed-off-by: Álvaro Fernández Rojas <[email protected]>