anv: fix struct anv_pipeline_stage stack overflows regression

Due to a regression, ShooterGame doesn't launch, it segfaults due to a stack overflow. This MR fixes the stack overflow.

Once you get past that, you'll see the game launches but it's a slide show. For that, you'll need !28285 (merged).

Fixes: ef8f0914 ("anv: add embedded sampler support")

The second patch is optional.