usbredir: Verify we have 32 bits bulk length cap when redirecting to xhci

The xhci-hcd may submit bulk transfers > 65535 bytes even when not using
bulk-in pipeling, so usbredir can only be used in combination with an xhci
hcd if the client has the 32 bits bulk length capability.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
