oml: Mention the SAPI that is activated in the log message
oml: Mention the SAPI that is activated in the log message

I was wondering why the channel was activated twice but it needs
to be activated for each SAPI.

osmocom/osmo-bts,shimaore/osmo-bts,shimaore/osmo-bts,telenoobie/osmo-bts,osmocom/osmo-bts,tacooper/osmo-bts,shimaore/osmo-bts,geosphere/osmo-bts,geosphere/osmo-bts,telenoobie/osmo-bts,geosphere/osmo-bts,tacooper/osmo-bts,telenoobie/osmo-bts,telenoobie/osmo-bts,shimaore/osmo-bts,osmocom/osmo-bts,geosphere/osmo-bts