Replacing fs_mgr_read_fstab() with new fs_mgr APIs

The fstab settings of early-mounted partitions (e.g., /vendor)
will be in kernel device tree. Switch to the new API to get the
whole settings with those in device tree:

    fs_mgr_read_fstab_with_dt("/fstab.device")

The original default /fstab.{ro.hardware} might be moved to
/vendor/etc/. or /odm/etc/. Use another new API to get the default
fstab instead of using the hard-coded /fstab.{ro.hardware}.
This API also includes the settings from device tree:

    fs_mgr_read_fstab_default()

Bug: 35811655
Test: build pass
Change-Id: I14bee88b9f599b7bbc2be56042684709e5946de2
1 file changed