tlshd: Update netlink.h

Add the definition for the new "tag" attribute. Copied from the
Linux kernel's include/uapi/linux/handshake.h .

Signed-off-by: Chuck Lever <[email protected]>

Author: chucklever

src/tlshd/netlink.h

@@ -55,6 +55,7 @@ enum {
 	HANDSHAKE_A_DONE_STATUS = 1,
 	HANDSHAKE_A_DONE_SOCKFD,
 	HANDSHAKE_A_DONE_REMOTE_AUTH,
+	HANDSHAKE_A_DONE_TAG,
 
 	__HANDSHAKE_A_DONE_MAX,
 	HANDSHAKE_A_DONE_MAX = (__HANDSHAKE_A_DONE_MAX - 1)