qseecom: Add support for key management scheme

Add IOCTLs and APIs for creating and wiping CE HW pipe Keys.
CE HW PIPE keys are not accessible by HLOS (xpu protected
by secure domain).  So, HLOS needs to request TZ to set/clear
these PIPE key registers.

This patch adds support for issuing commands to TZ to generate
and wipe keys.

Change-Id: I43777bf20be4f82e37ca39b81b9a9e862e47cea7
Signed-off-by: Mona Hossain <mhossain@codeaurora.org>