Fix error in indev driver template (#1476)

porting/lv_port_indev_template.c

@@ -140,14 +140,14 @@ void lv_port_indev_init(void)
 
     /*Register a encoder input device*/
     lv_indev_drv_init(&indev_drv);
-    indev_drv.type = LV_INDEV_TYPE_KEYPAD;
+    indev_drv.type = LV_INDEV_TYPE_ENCODER;
     indev_drv.read_cb = encoder_read;
     indev_encoder = lv_indev_drv_register(&indev_drv);
 
     /* Later you should create group(s) with `lv_group_t * group = lv_group_create()`,
      * add objects to the group with `lv_group_add_obj(group, obj)`
      * and assign this input device to group to navigate in it:
-     * `lv_indev_set_group(indev_keypad, group);` */
+     * `lv_indev_set_group(indev_encoder, group);` */
 
     /*------------------
      * Button