imx: hab: Ensure the IVT DCD pointer is Null prior to calling HAB authenticate function.

imx: hab: Ensure the IVT DCD pointer is Null prior to calling HAB authenticate function.

DCD commands should only be present in the initial boot image loaded by
the SoC ROM. DCD should not be present in images that will be verified
by software using HAB RVT authentication APIs. Newer versions of HAB
will generate an error if a DCD pointer is present in an image being
authenticated by calling the HAB RVT API. Older versions of HAB will
process and run DCD if it is present, and this could lead to an incorrect
authentication boot flow.

It is highly recommended this check is in place to ensure additional HAB
verified images do not include a DCD table.

Signed-off-by: Utkarsh Gupta <utkarsh.gupta@nxp.com>
Signed-off-by: Breno Lima <breno.lima@nxp.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>