Fix DEBUG_TCGV compile error.

Don't call TCGV_LOW on arg2.  This section of code falls under

Signed-off-by: Nathan Froyd <froydnj@codesourcery.com>
Acked-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6585 c046a42c-6fe2-441c-8c8c-71466251a162