Support numpad on newer macppc Apple PowerBooks

Support numpad on newer macppc Apple PowerBooks

This is for newer PowerBooks with ukbd(4), and doesn't affect older
models with akbd(4).  The Fn key now makes a numpad,

     7  8  9  0  -          7  8  9  /  =
      U  I  O  P      =>     4  5  6  *
       J  K  L  ;             1  2  3  -
           M  .  /                0  .  +

Also, Fn+F6 is Num Lock.  This acts like Num Lock on other USB
keyboards, and unlike Num Lock on akbd(4).

From jon (at) elytron (dot) openbsd (dot) amsterdam