It depends on what type of L2VPN we are talking about.
If we are talking about VPLS (where we learn from the data path) changes
are needed in order to make it work with segment routing. Basically, the
VC label must be assigned and used in such a way that it indicates not only
the service for the packet, but also the PE from which it originated. That
is because with SR, we would have lost the path (PW) that the packet used
to get to the destination PE.
If we are talking about BGP E-VPN where data path learning is not used,
then it should work with segment routing without any changes.
Anoop