vulkan: silence -Wint-conversion on 32-bit architectures

render/vulkan/renderer.c:388:70: error: incompatible pointer to integer conversion passing 'void *' to parameter of type 'VkFence' (aka 'unsigned long long') [-Werror,-Wint-conversion]
        VkResult res = vkQueueSubmit(renderer->dev->queue, 1, &submit_info, NULL);
                                                                            ^~~~
render/vulkan/renderer.c:1141:81: error: incompatible pointer to integer conversion passing 'void *' to parameter of type 'VkFence' (aka 'unsigned long long') [-Werror,-Wint-conversion]
        VkResult res = vkQueueSubmit(renderer->dev->queue, submit_count, submit_infos, NULL);
                                                                                       ^~~~
/usr/include/sys/_null.h:34:14: note: expanded from macro 'NULL'
 #define NULL    ((void *)0)
                 ^~~~~~~~~~~
/usr/local/include/vulkan/vulkan_core.h:4054:49: note: passing argument to parameter 'fence' here
    VkFence                                     fence);
                                                ^

Fixes: a8a194d695 ("render/vulkan: switch to timeline semaphores")

render/vulkan/renderer.c

@@ -385,7 +385,7 @@ bool vulkan_submit_stage_wait(struct wlr_vk_renderer *renderer) {
 		.signalSemaphoreCount = 1,
 		.pSignalSemaphores = &renderer->timeline_semaphore,
 	};
-	VkResult res = vkQueueSubmit(renderer->dev->queue, 1, &submit_info, NULL);
+	VkResult res = vkQueueSubmit(renderer->dev->queue, 1, &submit_info, VK_NULL_HANDLE);
 	if (res != VK_SUCCESS) {
 		wlr_vk_error("vkQueueSubmit", res);
 		return false;
@@ -1138,7 +1138,7 @@ static void vulkan_end(struct wlr_renderer *wlr_renderer) {
 	};
 
 	uint32_t submit_count = sizeof(submit_infos) / sizeof(submit_infos[0]);
-	VkResult res = vkQueueSubmit(renderer->dev->queue, submit_count, submit_infos, NULL);
+	VkResult res = vkQueueSubmit(renderer->dev->queue, submit_count, submit_infos, VK_NULL_HANDLE);
 	if (res == VK_ERROR_DEVICE_LOST) {
 		wlr_log(WLR_ERROR, "vkQueueSubmit failed with VK_ERROR_DEVICE_LOST");
 		wl_signal_emit_mutable(&wlr_renderer->events.lost, NULL);