boards: fvp v8r: Fix the SRAM/FLASH to the right address

Fix SRAM base address to 0x0 and set the size to 128M
Fix FLASH base address to 0x88000000 and set the size to 64MB

Signed-off-by: Jaxson Han <jaxson.han@arm.com>
(cherry picked from commit 357aacab)