powerpc/p1010rdb: SECURE BOOT- enable workaround for IFC errata A003399

The workaround for IFC errata A003399 was not enabled
in case of secure boot. So, secure boot from NOR was not
working.

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