sun50i: a64: Add initial Banana Pi M64 support

sun50i: a64: Add initial Banana Pi M64 support

BPI-M64 is a 64-bit quad-core mini single board computer
using the Allwinner A64 SOC.

BPI-M64 features
- 1.2 Ghz Quad-Core ARM Cortex A53
- 2GB DDR3 SDRAM with 733MHz
- MicroSD/eMMC(8GB)
- 10/100/1000Mbps ethernet (Realtek RTL8211E/D)
- Wifi + BT
- IR receiver
- Audio In/Out
- Video In/Out
- 5V 2A DC power-supply

For dts file,
Sync with Linux commit 4879b7ae("Merge tag 'dmaengine-4.12-rc1'").

Boot from MMC:
-------------
U-Boot SPL 2017.05-00667-g85dd258-dirty (May 29 2017 - 13:07:31)
DRAM: 2048 MiB
Trying to boot from MMC1
NOTICE:  BL3-1: Running on A64/H64 (1689) in SRAM A2 (@0x44000)
NOTICE:  Configuring SPC Controller
NOTICE:  BL3-1: v1.0(debug):aa75c8d
NOTICE:  BL3-1: Built : 18:28:27, May 24 2017
NOTICE:  Configuring AXP PMIC
NOTICE:  PMIC: setup successful
INFO:    BL3-1: Initializing runtime services
INFO:    BL3-1: Preparing for EL3 exit to normal world
INFO:    BL3-1: Next image address: 0x4a000000, SPSR: 0x3c9

U-Boot 2017.05-00667-g85dd258-dirty (May 29 2017 - 13:07:31 +0000) Allwinner Technology

CPU:   Allwinner A64 (SUN50I)
Model: BananaPi-M64
DRAM:  2 GiB
MMC:   SUNXI SD/MMC: 0, SUNXI SD/MMC: 1
*** Warning - bad CRC, using default environment

In:    serial
Out:   serial
Err:   serial
Net:   No ethernet found.
starting USB...
No controllers found
Hit any key to stop autoboot:  0

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>