dm-crypt: Skip encryption if bio is fscrypto or blk-crypto encrypted

Skip encryption of bio if it is already fs-crypto encrypted or is
supposed to be encrypted by blk-crypto.

Change-Id: I89053a2e0a63941265f5973f2f78786e69f0db37
Signed-off-by: Neeraj Soni <neersoni@codeaurora.org>