vc4: Fix raster surface shadow updates under DRI2.
vc4: Fix raster surface shadow updates under DRI2.

Glamor asks GBM for the handle of the BO, then flinks it itself.  We
were marking the bo non-private in the flink and dmabuf (DRI3) paths,
but not the GEM handle path.  As a result, non-pageflipping DRI2
swapbuffers (EGL apps, in particular) were never updating the texture.

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler