decoder/gme: use integer seek times

src/decoder/plugins/GmeDecoderPlugin.cxx

@@ -194,8 +194,8 @@ gme_file_decode(Decoder &decoder, Path path_fs)
 
 		cmd = decoder_data(decoder, nullptr, buf, sizeof(buf), 0);
 		if (cmd == DecoderCommand::SEEK) {
-			float where = decoder_seek_where(decoder);
-			gme_err = gme_seek(emu, int(where * 1000));
+			unsigned where = decoder_seek_where_ms(decoder);
+			gme_err = gme_seek(emu, where);
 			if (gme_err != nullptr)
 				LogWarning(gme_domain, gme_err);
 			decoder_command_finished(decoder);