sunxi: Groundwork to support new dram type for A83T

sunxi: Groundwork to support new dram type for A83T

Different A83T boards have different DRAM types. Banapi M3 has LPDDR3,
Allwinner Homlet v1.2 has DDR3.

This adds groundwork to support for new DRAM type for A83T.

Introduce CONFIG_DRAM_TYPE, It'll be 3 for DDR3 and 7 for LPDDR3, must
be set in respective board defconfig.

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