sunxi: add Linksprite pcDuino v1/v2 support

sunxi: add Linksprite pcDuino v1/v2 support

Add support for a sun4i board built by Linksprite. This addition covers
both v1 and v2 versions. As the board has been working with 408MHz memory
setting in the u-boot-sunxi branch, and has been proven to be running stable
during my tests as well, a respective new DRAM config file is added as well.

Signed-off-by: Zoltan HERPAI <wigyori@uid0.hu>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>