md: Performance improvement for ICE based FDE

Since ICE based solution does encryption in storage, there is no
need to keep the BIOs allocated. Adding a new constant that would
be used by ICE driver to detect ICE based DM solution and configure
requests correctly.

Change-Id: I8d52d55679e638a5eea066a1d62b8f617f1472ef
Signed-off-by: Dinesh K Garg <dineshg@codeaurora.org>