The target-dependant type TCGv must be defined in "tcg/tcg.h" before
including the tracing helper wrappers in "tcg/tcg-op.h".

It also makes more sense to define it here, where other TCG types are
defined too.

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 145641860129.30295.17554707227384022653.stgit@localhost
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>