Fix the compatibility typedef of ioservid_t to match the Xen headers

Fix the compatibility typedef of ioservid_t to match the Xen headers

There is a mismatch between the definition of ioservid_t in
xen_common.h and the definition in the Xen public headers. This patch
corrects the definition in xen_common.h.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Tested-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1436275958-25174-1-git-send-email-paul.durrant@citrix.com
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>