fix(MdFile): Remove calling method onInput which doesn't exist (#1176)

fix #1163

Author: VdustR

src/components/MdField/MdFile/MdFile.vue

@@ -62,7 +62,6 @@
       },
       onChange ($event) {
         this.onFileSelected($event)
-        this.onInput()
       },
       onFileSelected ({ target, dataTransfer }) {
         const files = target.files || dataTransfer.files