Introduce the req_iu() helper which returns a pointer to
the viosrp_iu union held in the vscsi_req structure.
This simplifies the next patch.
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200305121253.19078-5-philmd@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>