tools: add IFLA_XFRM_COLLECT_METADATA to uapi/linux/if_link.h

Needed for XFRM metadata tests.
Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
Link: https://lore.kernel.org/r/20221203084659.1837829-4-eyal.birger@gmail.comSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>

tools/include/uapi/linux/if_link.h

@@ -673,6 +673,7 @@ enum {
 	IFLA_XFRM_UNSPEC,
 	IFLA_XFRM_LINK,
 	IFLA_XFRM_IF_ID,
+	IFLA_XFRM_COLLECT_METADATA,
 	__IFLA_XFRM_MAX
 };