imx: imx7 Support for Manufacturing Protection

imx: imx7 Support for Manufacturing Protection

This code was originally developed by Raul Cardenas <raul.casas@nxp.com>
and modified to be applied in U-Boot imx_v2017.03.

More information about the initial submission can be seen
in the link below:
https://lists.denx.de/pipermail/u-boot/2016-February/245273.html

i.MX7D has an a protection feature for Manufacturing process.
This feature uses asymmetric encryption to sign and verify
authenticated software handled between parties. This command
enables the use of such feature.

The private key is unique and generated once per device.
And it is stored in secure memory and only accessible by CAAM.
Therefore, the public key generation and signature functions
are the only functions available for the user.

The manufacturing-protection authentication process can be used to
authenticate the chip to the OEM's server.

Command usage:

Print the public key for the device.
- mfgprot pubk

Generates Signature over given data.
- mfgprot sign <data_address> <data_size>

Signed-off-by: Raul Ulises Cardenas <raul.casas@nxp.com>
Signed-off-by: Breno Lima <breno.lima@nxp.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>