dm: dm-req-crypt: add support for Per-File-Encryption

Support Per-File-Encryption (PFE) based on file tagging.
The Per-File-Tagger (PFT) reports if a file should be encrypted or not.
The Per-File-Encryption can be used after Full-Disk-Encryption (FDE) was
completed or without FDE.
The PFE and FDE uses different keys, which are managed by the Trust-Zone.

Change-Id: I727ef11e252649f895a5e3f8a49ca848cea50795
Signed-off-by: Amir Samuelov <amirs@codeaurora.org>