Fix c6c3d0e6: restore string-based settings in network-private settings (#10765)

By accident the SDTC_SSTR got replaced with SDTC_VAR, which breaks
many of the settings in this file.

src/table/settings/network_private_settings.ini

@@ -15,11 +15,10 @@ static const SettingVariant _network_private_settings_table[] = {
 [templates]
 SDTC_BOOL  =  SDTC_BOOL(              $var,        $flags, $def,                              $str, $strhelp, $strval, $pre_cb, $post_cb, $from, $to,        $cat, $extra, $startup),
 SDTC_OMANY = SDTC_OMANY(              $var, $type, $flags, $def,             $max, $full,     $str, $strhelp, $strval, $pre_cb, $post_cb, $from, $to,        $cat, $extra, $startup),
-SDTC_VAR   =   SDTC_VAR(              $var, $type, $flags, $def,       $min, $max, $interval, $str, $strhelp, $strval, $pre_cb, $post_cb, $from, $to,        $cat, $extra, $startup),
+SDTC_SSTR  =  SDTC_SSTR(              $var, $type, $flags, $def,             $length,                                  $pre_cb, $post_cb, $from, $to,        $cat, $extra, $startup),
 
 [validation]
 SDTC_OMANY = static_assert($max <= MAX_$type, "Maximum value for $var exceeds storage size");
-SDTC_VAR = static_assert($max <= MAX_$type, "Maximum value for $var exceeds storage size");
 
 [defaults]
 flags    = SF_NONE