drivers: remoteproc: ti_k3 : enable secure booting with firmware images

drivers: remoteproc: ti_k3 : enable secure booting with firmware images

Remoteproc firmware images aren't authenticated in the current boot flow.
Authenticates remoteproc firmware images to complete the root of trust
in secure booting.

Signed-off-by: Manorit Chawdhry <m-chawdhry@ti.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> # Intel Edison
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>