Add support for board based on the Altera Cyclone V SoC.
This board has the following functions:
    - 1 GiB of DRAM
    - 1 Gigabit ethernet
    - 1 SD card slot
    - 1 USB gadget port
    - QSPI NOR Flash
    - I2C EEPROMs and I2C RTC
    - DVI output
    - Audio port

This commit supports without QSPI, DVI and Audio.
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>