I went to wiktionary.org to check which languages that have a name for Finland related to "Finland" rather than "Suomi" or something else spell it with 2 n rather than 1.
Finnland: German, Old Norse, Faroese, Icelandic
Finnia: Latin (alternatively also Finlandia, with 1 n)
Finnlynn: Manx
an Fhionnlainn: Scottish Gaelic (alternatively also Suòmaidh)
Finnország: Hungarian