rusticl/mesa/context: use Default for pipe_grid_info initialization

Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32821>

src/gallium/frontends/rusticl/mesa/pipe/context.rs

@@ -397,20 +397,11 @@ impl PipeContext {
         variable_local_mem: u32,
     ) {
         let info = pipe_grid_info {
-            pc: 0,
-            input: ptr::null(),
             variable_shared_mem: variable_local_mem,
             work_dim: work_dim,
             block: block,
-            last_block: [0; 3],
             grid: grid,
-            grid_base: [0; 3],
-            indirect: ptr::null_mut(),
-            indirect_offset: 0,
-            indirect_stride: 0,
-            draw_count: 0,
-            indirect_draw_count_offset: 0,
-            indirect_draw_count: ptr::null_mut(),
+            ..Default::default()
         };
         unsafe { self.pipe.as_ref().launch_grid.unwrap()(self.pipe.as_ptr(), &info) }
     }