The original pass only looked for load_uniform intrinsics but there are
a number of other places that could end up loading a push constant.  One
obvious omission was images which always implicitly use a push constant.
Legacy VS clip planes also get pushed into the shader.  This fixes some
new Vulkan CTS tests that test random combinations of bindings and, in
particular, test lots of UBOs and images together.

Cc: mesa-stable@lists.freedesktop.org
Cc: Kenneth Graunke <kenneth@whitecape.org>