radv: fix crash in shader tracing.

Enabling tracing, and then having a vmfault, can leads to a segfault
before we print out the traces, as if a meta shader is executing
and we don't have the NIR for it.

Just pass the stage and give back a default.

Fixes: 9b9ccee4d6 ("radv: take LDS into account for compute shader occupancy stats")
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>

src/amd/vulkan/radv_shader.c

@@ -1234,7 +1234,7 @@ generate_shader_stats(struct radv_device *device,
 				     lds_increment);
 	} else if (stage == MESA_SHADER_COMPUTE) {
 		unsigned max_workgroup_size =
-				radv_nir_get_max_workgroup_size(chip_class, variant->nir);
+			radv_nir_get_max_workgroup_size(chip_class, stage, variant->nir);
 		lds_per_wave = (conf->lds_size * lds_increment) /
 			       DIV_ROUND_UP(max_workgroup_size, 64);
 	}