Pointers in ESBC header made 32 bit

Pointers in ESBC header made 32 bit

For the Chain of Trust, the esbc_validate command supports
32 bit fields for location of the image. In the header structure
definition, these were declared as pointers which made them
64 bit on a 64 bit core.

Signed-off-by: Aneesh Bansal <aneesh.bansal@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>