Change fs-verity setup to the new format

This is due to upstream kernel API change.  With simpler API, many setup
code can now be removed.

Test: atest com.android.cts.apkverity.ApkVerityTest
Bug: 112037636
Change-Id: Ie88d55630b5d20ddbcbea4be7af9cf1fee47e44a
3 files changed