[Lima] [PATCH v2 6/8] gallium: add lima driver

[Alyssa Rosenzweig]

> Seems Panfrost implementation does not take depth uniforms?

That's a /* to-do */ for me; it should definitely be implemented before
adding to common code.

> we both use the viewport scale/transform vector as the uniform
> in this lower pass.

I think that's reasonable. I don't like wasting a half-uniform (2vec3 =
1.5vec4), but that can't be helped I guess.

> But due to lima pad special uniforms instead of prefix like
> panfrost, we need to add a uniform location parameter to the API function.

What do you mean by "pad vs prefix"? A location parameter is a good idea
regardless. Better yet, we could use an intrinsic system value load (I
forget the exact) name to handle this, which I think is the most generic
way for common NIR routines.