vold: replacing fs_mgr_read_fstab() with fs_mgr_read_fstab_default()

The original default /fstab.{ro.hardware} might be moved to /vendor/etc/.
or /odm/etc/. Use the new API to get the default fstab instead of using
the hard-coded /fstab.{ro.hardware}.

Bug: 35811655
Test: boot marlin with /vendor/etc/fstab.marlin
Change-Id: I92d6aefe6ff3433b7d1a671358d990bb7b1f2150
4 files changed