configs: sunxi: licheepi_nano: enable D-Cache

As the compile error when D-Cache is enabled is gone, we can have
D-Cache enabled now.

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>