Add A8 surface capability
Add A8 surface capability

Even though the ability to handle a8 surfaces was added at the same
time as the composite command, they are logically separate, so add a
capability bit to indicate the presence of a8 surfaces.

fgouget/spice-protocol,Fantu/spice-protocol,vdiot/spice-protocol,vdiot/spice-protocol,vdiot/spice-protocol,fgouget/spice-protocol,freedesktop-unofficial-mirror/spice__spice-protocol,Fantu/spice-protocol,freedesktop-unofficial-mirror/spice__spice-protocol,elmarco/spice-protocol,elmarco/spice-protocol,fgouget/spice-protocol,SPICE/spice-protocol,SPICE/spice-protocol,elmarco/spice-protocol,SPICE/spice-protocol