chore(timepicker): add bind once to template

- Add bind once to appropriate values not being watched in template

Closes #3809

template/timepicker/timepicker.html

@@ -8,11 +8,11 @@
     </tr>
     <tr>
       <td class="form-group" ng-class="{'has-error': invalidHours}">
-        <input style="width:50px;" type="text" ng-model="hours" ng-change="updateHours()" class="form-control text-center" ng-readonly="readonlyInput" maxlength="2">
+        <input style="width:50px;" type="text" ng-model="hours" ng-change="updateHours()" class="form-control text-center" ng-readonly="::readonlyInput" maxlength="2">
       </td>
       <td>:</td>
       <td class="form-group" ng-class="{'has-error': invalidMinutes}">
-        <input style="width:50px;" type="text" ng-model="minutes" ng-change="updateMinutes()" class="form-control text-center" ng-readonly="readonlyInput" maxlength="2">
+        <input style="width:50px;" type="text" ng-model="minutes" ng-change="updateMinutes()" class="form-control text-center" ng-readonly="::readonlyInput" maxlength="2">
       </td>
       <td ng-show="showMeridian"><button type="button" class="btn btn-default text-center" ng-click="toggleMeridian()">{{meridian}}</button></td>
     </tr>