vrend: Check glTextureView feature before using it
requested to merge akihiko.odaki/virglrenderer:vrend-check-gltextureview-feature-before-using-it into master
This fixes the regression introduced with commit 45eb512a43e257427617699e3849ca93434c1717c and 62cc6ed6.
Signed-off-by: Akihiko Odaki akihiko.odaki@gmail.com