Original Nokia BTS support in OsmoBSC was limited to MetroSite, UltraSite and InSite, aka the Site family. After the recent series of fixes, the same code also supports Flexi Multiradio (actively used in the present) and will most likely also work on Flexi EDGE (intermediate between UltraSite and Flexi MR), although that model is currently untested.
BTS model name "nokia_site" is thus outdated and inaccurate now. It has been decided (see https://gerrit.osmocom.org/c/osmo-bsc/+/42729) to keep this model name unchanged for now, given the uncertainty of how Nokia BTS support will evolve in the future if and when we implement support for IP Abis on Flexi family, potentially followed by future support for subsequent IP-only models.
In the meantime, change vty help string to reflect current support for both Site and Flexi families with the same model selection.
