sunxi: Add Machine Support for A83T SOC

Allwinner A83T is octa-core cortex-a7 SOC.
This enables support for A83T.

SMP is not yet supported.

Signed-off-by: Vishnu Patekar <vishnupatekar0510@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>