gallivm/nir: Lower uniforms to UBOs in llvm draw if the driver didn't request this already

When the llvm draw engine is used for draw shaders in st_program the driver
may not enable the cap PIPE_CAP_PACKED_UNIFORMS, so uniforms are not
be lowered to UBOs. However, llvm doesn't support nir_load_uniform, so lower
the uniforms to UBO now. The multiplier is set to 16 to be the same like in
the TGSI code path.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5681>
diff --git a/src/gallium/auxiliary/draw/draw_vs_llvm.c b/src/gallium/auxiliary/draw/draw_vs_llvm.c
index ec3c5b0..42551b9 100644
--- a/src/gallium/auxiliary/draw/draw_vs_llvm.c
+++ b/src/gallium/auxiliary/draw/draw_vs_llvm.c
@@ -98,6 +98,8 @@
       for ir.nir & PIPE_SHADER_IR_NIR here. */
    if (state->ir.nir && state->type == PIPE_SHADER_IR_NIR) {
       vs->base.state.ir.nir = state->ir.nir;
+      if (!draw->pipe->screen->get_param(draw->pipe->screen, PIPE_CAP_PACKED_UNIFORMS))
+         NIR_PASS_V(state->ir.nir, nir_lower_uniforms_to_ubo, 16);
       nir_tgsi_scan_shader(state->ir.nir, &vs->base.info, true);
    } else {
       /* we make a private copy of the tokens */