Call access(2) on all files/dirs modified by Mtp

External sdcards are accessed through /mnt/media_rw,
so access() each touched file for sdcardfs to update
its metadata. This is done for all created/deleted/renamed
folders and files.

Bug: 77849654
Test: use mtp with emulated sdcard
Change-Id: Ic8cef9dc90e9cbc9783ff45a87c481833f910665