xfrm: clone XFRMA_SET_MARK in xfrm_do_migrate

XFRMA_SET_MARK and XFRMA_SET_MARK_MASK was not cloned from the old
to the new. Migrate these two attributes during XFRMA_MSG_MIGRATE

Fixes: 9b42c1f1 ("xfrm: Extend the output_mark to support input direction and masking.")
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>