pfk: Added support for virtualized ICE

Added pfk_ice_virt.c which sends hab requests to BE in host,
instead of sending scm calls directly to TZ.
Also, removed the hardcoded size of key cache table,
and made it configurable.

Change-Id: I942c3886c2fb93846bcdf15b19eabb3bc83e05ba
Signed-off-by: Shay <shayn@codeaurora.org>