radv: Replace an assert with unreachable.

Otherwise we get uninitialized variable warnings for es_vgpr_comp_cnt.

Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>

src/amd/vulkan/radv_shader.c

@@ -424,7 +424,7 @@ radv_fill_shader_variant(struct radv_device *device,
 		} else if (es_type == MESA_SHADER_TESS_EVAL) {
 			es_vgpr_comp_cnt = 3;
 		} else {
-			assert(!"invalid shader ES type");
+			unreachable("invalid shader ES type");
 		}
 
 		/* If offsets 4, 5 are used, GS_VGPR_COMP_CNT is ignored and