patch applied (ghc): fix a case of " naughty I386 byte reg"

[Simon Marlow]

Tue Jun  6 04:23:57 PDT 2006  Simon Marlow <simonmar at microsoft.com>
  * fix a case of "naughty I386 byte reg"
  The fix is a little hacky, because we don't have support for register
  classes in general, but it's an improvement.

    M ./compiler/nativeGen/MachCodeGen.hs -12 +22