PFK: new module to work with ecryptfs

PFK is a new module that accompanies eCryptfs and
enables it to utilize ICE hw encryption engine. Module
is responsible for storing encryption/decryption keys
inside eCryptfs inodes for each file and loading them
to ICE

Change-Id: I6e755ca657164919147fe0d9482477e14a4be5eb
Signed-off-by: Andrey Markovytch <andreym@codeaurora.org>