vatrace: only print info of valid reference frames
vatrace: only print info of valid reference frames

Signed-off-by: Austin Yuan <f447c34e4ebcef84a81b40a8d4dbc448a14e5570@intel.com>
(cherry picked from commit 67c489f323188df1370f8ba2d4063bc86153cce7)

gbeauchesne/libva,01org/libva-cros,01org/iotg-lin-gfx-libva,01org/iotg-lin-gfx-libva,gbeauchesne/libva,pma1/libva,chenxianqin/vaapi-libva,gbeauchesne/libva,chenxianqin/vaapi-libva,zzhhui/libva,01org/libva-cros,pma1/libva,01org/iotg-lin-gfx-libva,chenxianqin/vaapi-libva,zzhhui/libva,pma1/libva,zzhhui/libva,01org/libva-cros