xfrm: clone whole liftime_cur structure in xfrm_do_migrate

[ Upstream commit 8366685b ]

When we clone state only add_time was cloned. It missed values like
bytes, packets.  Now clone the all members of the structure.

v1->v3:
 - use memcpy to copy the entire structure

Fixes: 80c9abaa ("[XFRM]: Extension for dynamic update of endpoint address(es)")
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>