Update Inline Crypto Engine support for File based Encryption

Few changes done to better support ICE+FBE:
1. Check for ICE device support instead of mode while
   creating dummy context.
2. Support only AES-256 mode for file name encryption
   as of now for ICE based FBE.
3. Revert changes made on top of F2FS+FBE patch
   0017-fscrypt-updates-on-4.15-rc4.patch
   The change was done to fix boot up issue with this
   patch but now this can be reverted since fix is made
   to support bootup with this patch.

Change-Id: I839e2215db62ae9bebf1ba3b932395fb2555d315
Signed-off-by: Neeraj Soni <neersoni@codeaurora.org>