sunxi: Enable CONFIG_SYS_64BIT_LBA when AHCI is used

Due to absence of CONFIG_SYS_64BIT_LBA, u-boot-sunxi currently has
no support for the (GPT) partioning scheme of large disks > 2TB.
While the AHCI driver seems to handle this nicely, the problem is
that lbaint_t values get truncated to 32-bit.

This patch sets CONFIG_SYS_64BIT_LBA from sunxi_common.h for all
SoCs that support AHCI (CONFIG_SUNXI_AHCI).

Signed-off-by: Bernhard Nortmann <bernhard.nortmann@web.de>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>