mesalib: Enable VA-API support for some gallium drivers

Probably due to an outdated libva library, VA-API support wasn’t
enabled. Explicitly enable the support, so the problem is noticed in the
future.

•   /usr/lib/dri/nouveau_drv_video.so
•   /usr/lib/dri/r600_drv_video.so
•   /usr/lib/dri/radeonsi_drv_video.so

Resolves: https://gitlab.freedesktop.org/mesa/mesa/-/issues/7119#note_1521281

mesalib.be0

@@ -58,6 +58,7 @@ mee_configure() {
         -Dbuildtype=release \
         -Dgallium-drivers="crocus,iris,i915,nouveau,r600,radeonsi,svga,swrast" \
         -Dgallium-opencl="icd" \
+        -Dgallium-va=enabled \
         -Dvulkan-drivers="amd,intel" \
         -Dosmesa=true \
         -Dvalgrind=false \