BL31 runs from SRAM which is a non-coherent memory on synquacer. So
enable MMU with SRAM memory marked as Non-Cacheable and mark page tables
kept on SRAM as Non-Cacheable via XLAT_TABLE_NC flag. Also add page tables
for Device address space.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>