gstvaapifilter: Add guard for VAProcFilterSkinToneEnhancement
gstvaapifilter: Add guard for VAProcFilterSkinToneEnhancement

VAProcFilterSkinToneEnhancement is avaialbe from VA >= 0.36.

Signed-off-by: Sreerenj Balachandran <8526e100bdc7a12d85af109c9f42b86756e50e67@intel.com>

gbeauchesne/gstreamer-vaapi,gbeauchesne/gstreamer-vaapi,gbeauchesne/gstreamer-vaapi