habanalabs/gaudi2: change device f/w security check

On Gaudi2 the f/w always configures the PCIe iATU and allows access to
scratchpad registers. Therefore, we can know if the f/w is secured
by reading a status bit from the f/w registers.

Signed-off-by: farah kassabri <fkassabri@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>