to get DCMF status

Extend RSU driver to get DCMF status.

The status of each DCMF is reported. The currently used DCMF is used as
reference, while the other three are compared against it to determine if
they are corrupted.

DCMF = Decision Configuration Management Firmware.
RSU = Remote System Update

Signed-off-by: Radu Bacrau <[email protected]>