fix(corstone1000): change base address of FIP in the flash

More space in the flash is reserved up front for metadata
parser and UEFI variables. That requires change in the flash
base address of where images are present.

Signed-off-by: Satish Kumar <satish.kumar01@arm.com>
Signed-off-by: Vishnu Banavath <vishnu.banavath@arm.com>
Change-Id: Ieaabe09374d707de18d36505c69b6c9a8c2ec2e9