spirv: Handle the PixelCenterInteger execution mode.

This isn't allowed by Vulkan, but might be useful someday for
SPIR-V in OpenGL (if that ever becomes a thing).  It's easy enough
to hook up, and as precedent, we already do so for OriginLowerLeft.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
3 files changed