*/*: remove misplaced directive, it's model not form

benchmarks/iperf/src/opnsense/mvc/app/controllers/OPNsense/iperf/forms/instance_settings.xml

@@ -3,7 +3,6 @@
       <id>instance.interface</id>
       <label>Interface</label>
       <type>dropdown</type>
-      <multiple>N</multiple>
       <help>Choose the interface on which the port should be opened.</help>
    </field>
 </form>

net/mdns-repeater/src/opnsense/mvc/app/controllers/OPNsense/MDNSRepeater/forms/general.xml

@@ -9,7 +9,6 @@
       <id>mdnsrepeater.interfaces</id>
       <label>Listen Interfaces</label>
       <type>select_multiple</type>
-      <multiple>Y</multiple>
       <help>At least two interfaces must be selected.</help>
    </field>
 </form>