anv: Add trivial support for TrimCommandPoolKHR

Our command buffers already efficiently use a global pool so trimming
doesn't really need to do anything.

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>

src/intel/vulkan/anv_cmd_buffer.c

@@ -787,6 +787,14 @@ VkResult anv_ResetCommandPool(
    return VK_SUCCESS;
 }
 
+void anv_TrimCommandPoolKHR(
+    VkDevice                                    device,
+    VkCommandPool                               commandPool,
+    VkCommandPoolTrimFlagsKHR                   flags)
+{
+   /* Nothing for us to do here.  Our pools stay pretty tidy. */
+}
+
 /**
  * Return NULL if the current subpass has no depthstencil attachment.
  */