Secure Boot Target is added for NAND for P5020 and P5040.
The Secure boot target has already been added for P3041 by
enabling CONFIG_SYS_RAMBOOT and configuring CPC as SRAM.

The targets for P5020 and P5040 are added in the same manner.
Signed-off-by: NSaksham Jain <saksham@freescale.com>
Signed-off-by: NRuchika Gupta <ruchika.gupta@freescale.com>
Signed-off-by: NAneesh Bansal <aneesh.bansal@freescale.com>
Reviewed-by: NYork Sun <yorksun@freescale.com>