armv8/ls1043aqds: add LS1043AQDS board support

LS1043AQDS Specification:
-------------------------
Memory subsystem:
 * 2GByte DDR4 DIMM
 * 128 Mbyte NOR flash single-chip memory
 * 512 Mbyte NAND flash
 * 16 Mbyte high-speed SPI flash
 * SD connector to interface with the SD memory card

Ethernet:
 * Two RGMII ports
 * XFI 10G port
 * SGMII
 * QSGMII with 4x 1G ports

PCIe: supports Gen 1 and Gen 2

SATA 3.0: one SATA 3.0 port

USB 3.0: two micro AB connector and one type A connector

UART: supports two UARTs up to 115200 bps for console

Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Signed-off-by: Mingkai Hu <Mingkai.Hu@freescale.com>
Signed-off-by: Hou Zhiqiang <B48286@freescale.com>
Signed-off-by: Gong Qianyu <Qianyu.Gong@freescale.com>
[York Sun: Add CONFIG_SYS_NS16550=y in defconfig]
Reviewed-by: York Sun <yorksun@freescale.com>