speeding up (un)register_code16

speeding up (un)register_code16

In register_code16 and unregister_code16 we call register_code and
unregister_code twice, once for the mods and once for the keycode.
The (un)register_code have many check to see that keycode we have sent
however because we know that we are sending it a mods key, why not
just skip all of it and call (un)register_mods instead. This will skip
alot of checks and should speedup the loop a little.