anv: Add FIXME for vkResetCommandPool

vkResetCommandPool currently destroys its command buffers. The Vulkan
1.0 spec requires that it only reset them:

    Resetting a command pool recycles all of the resources from all of
    the command buffers allocated from the command pool back to the
    command pool. All command buffers that have been allocated from the
    command pool are put in the initial state.

src/vulkan/anv_cmd_buffer.c

@@ -1074,6 +1074,14 @@ VkResult anv_ResetCommandPool(
 {
    ANV_FROM_HANDLE(anv_cmd_pool, pool, commandPool);
 
+   /* FIXME: vkResetCommandPool must not destroy its command buffers. The
+    * Vulkan 1.0 spec requires that it only reset them:
+    *
+    *    Resetting a command pool recycles all of the resources from all of
+    *    the command buffers allocated from the command pool back to the
+    *    command pool. All command buffers that have been allocated from the
+    *    command pool are put in the initial state.
+    */
    list_for_each_entry_safe(struct anv_cmd_buffer, cmd_buffer,
                             &pool->cmd_buffers, pool_link) {
       anv_cmd_buffer_destroy(cmd_buffer);