xfrm: add capability reference to xfrmnl_sa_set_*
xfrm: add capability reference to xfrmnl_sa_set_*

Just for consistency(tm)'s sake: add the reference to what capability
introduced the modified API.

Signed-off-by: Thomas Egerer <99ef75c122afe73dd03e0ee223f77d9a52aa8c0f@gmx.de>

tklauser/libnl,greearb/libnl-ct,tklauser/libnl,HolyShitMan/libnl-1,dsahern/libnl,HolyShitMan/libnl-1,thom311/libnl,dsahern/libnl,dsahern/libnl,tklauser/libnl,greearb/libnl-ct,dsahern/libnl,tklauser/libnl,thom311/libnl,HolyShitMan/libnl-1,greearb/libnl-ct,HolyShitMan/libnl-1,thom311/libnl