lavapipe: zero-init pipe_sampler_state

makes trace more reliable

Reviewed-by: Dave Airlie <airlied@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24568>

src/gallium/frontends/lavapipe/lvp_device.c

@@ -2360,7 +2360,7 @@ VKAPI_ATTR VkResult VKAPI_CALL lvp_CreateSampler(
    vk_object_base_init(&device->vk, &sampler->base,
                        VK_OBJECT_TYPE_SAMPLER);
 
-   struct pipe_sampler_state state;
+   struct pipe_sampler_state state = {0};
    VkClearColorValue border_color =
       vk_sampler_border_color_value(pCreateInfo, NULL);
    STATIC_ASSERT(sizeof(state.border_color) == sizeof(border_color));