umount /data/user/0 before umount /data

FDE device has shut down and restart the framework.
But restart is not triggered due to umount fail.
umount /data fail with "device is busy"
It is because bind mount /data/data to /data/user/0

We need umount /data/user/0 before umount /data

Bug: 148004718
Test: Flash GSI and check boot with FDE and FBE device.
Change-Id: I919f9e31a9d2d745b297a7ab99b399aa9b293b39
Merged-In: I919f9e31a9d2d745b297a7ab99b399aa9b293b39
(cherry picked from commit 3cf3233b)