Fm2Import - warn about ignoring the famicom port, instead of a full error, apparently movies can have this port set, but to none, so importing the movie can still be successful, for example: http://tasvideos.org/6739S.html, fixes #1989

src/BizHawk.Client.Common/movie/import/Fm2Import.cs

@@ -139,8 +139,7 @@ namespace BizHawk.Client.Common
 				{
 					if (ParseHeader(line, "port2") == "1")
 					{
-						Result.Errors.Add("Famicom port not yet supported");
-						break;
+						Result.Warnings.Add("Famicom port detected but not yet supported, ignoring");
 					}
 				}
 				else if (line.ToLower().StartsWith("fourscore"))