zink: do not use SpvDimRect

Vulkan doesn't support SpvDimRect. But we don't need to pass this at
all, as we already mark the sampler as un-normalized.

Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3764>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3764>
2 files changed