anv: fix memory allocation error handling

Reported by Coverity.

Fixes: 0a7224f3ff ("anv: group as many command buffers into a single execbuf")
Signed-off-by: Marcin Ślusarz <marcin.slusarz@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9596>

src/intel/vulkan/anv_queue.c

@@ -1290,7 +1290,7 @@ anv_queue_submit_post_and_alloc_new(struct anv_queue *queue,
       return result;
 
    *submit = anv_queue_submit_alloc(queue->device, perf_pass);
-   if (!submit)
+   if (!*submit)
       return vk_error(VK_ERROR_OUT_OF_HOST_MEMORY);
    return VK_SUCCESS;
 }