All Nokia-specific vty settings previously had names beginning with nokia_site, creating needless confusion for operators of Nokia BTS models that are newer than *Site family. Rename these vty settings to begin with just nokia, with nokia_site supported as a backward compatibility alias.
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BTS model name "nokia_site" is thus outdated and inaccurate now.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.
The switch statement on (bts->type) in this function exhibited two defects:
1) From the beginning, each unhandled BTS type was listed explicitly, instead of providing a default case;
2) When Nokia-specific initialization was added in 2015, the addition was erroneously applied to GSM_BTS_TYPE_BS11 and GSM_BTS_TYPE_UNKNOWN cases, besides the intended case of GSM_BTS_TYPE_NOKIA_SITE.
