soc: qcom: spss_utils: IAR fix CE after SSR - read cmacs from DDR on demand

After updating SPU images, if SSR occurred SPU would recalculate
the images cmacs and write them to DDR.
HLOS read those cmacs too early before SPU finished the calculation,
causing a CE.
The fix - when userspace asks for the calculated cmacs,
read them directly from DDR, instead of returning
cmacs that were already saved.

Change-Id: I0010a94eace107301652f20fbc62bbd66eda9ec3
Signed-off-by: Dan Bar-On <dbaron@codeaurora.org>