spice.h: remove redundant declarations
spice.h: remove redundant declarations

Those are already declared in <spice/qxl_dev.h>.

Fantu/spice,SPICE/spice,fgouget/spice,Fantu/spice,SPICE/spice,Fantu/spice,SPICE/spice,ya-mouse/spice,fgouget/spice,ya-mouse/spice,fgouget/spice,freedesktop-unofficial-mirror/spice__spice,ya-mouse/spice,freedesktop-unofficial-mirror/spice__spice,Fantu/spice,freedesktop-unofficial-mirror/spice__spice,freedesktop-unofficial-mirror/spice__spice,fgouget/spice,freedesktop-unofficial-mirror/spice__spice