De-virtualize V_pf_mtag_z to eliminate kernel panics.

[Gleb Smirnoff]

  Craig,

  right now Nikos Vassiliadis <nvass gmx.com> is working on
vimaging the pf properly. I'd leave decision on whether pf
mtag zone should be V or not to him.

  He is now a bit busy with real life, so patching pf is on
hiatus. I hope he will continue soon.

P.S.  The patch in the first mail isn't correct, as Marko explained.

-- 
Totus tuus, Glebius.