spiv: Make image cache functions No-Op when cache pointer is NULL.
spiv: Make image cache functions No-Op when cache pointer is NULL.

Spiv is not ready for the change though.

gfxprim/gfxprim,gfxprim/gfxprim,gfxprim/gfxprim,gfxprim/gfxprim,gfxprim/gfxprim