rockchip: rk3328: add defconfig for evb-rk3328

Enable board config for evb-rk3328.
SDcard and eMMC boot is OK in this initial version,
USB and EMAC function is not available now, will comes later.

Signed-off-by: William Zhang <william.zhang@rock-chips.com>
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>