board: synquacer: Add DeveloperBox 96boards EE support

board: synquacer: Add DeveloperBox 96boards EE support

Add the DeveloperBox 96boards EE support. This board is also
known as Socionext SynQuacer E-Series. It contians one "SC2A11"
SoC, which has 24-cores of arm Cortex-A53, and 4 DDR3 slots,
3 PCIe slots (1 4x port and 2 1x ports which are expanded via
PCIe bridge chip), 2 USB 3.0 ports and 2 USB 2.0 ports, 2 SATA
ports and 1 GbE, 64MB NOR flash and 8GB eMMC on standard
MicroATX Form Factor.

For more information, see this page;
  https://www.96boards.org/product/developerbox/

Signed-off-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>