SPDX: Convert all of our single license tags to Linux Kernel style

When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from. So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry. Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents. There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>

ls1046ardb: cpld: add API for selecting core volt

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>

armv8: ls1046ardb: Add LS1046ARDB board support

LS1046ARDB Specification:
-------------------------
Memory subsystem:
* 8GByte DDR4 SDRAM (64bit bus)
* 512 Mbyte NAND flash
* Two 64 Mbyte high-speed SPI flash
* SD connector to interface with the SD memory card
* On-board 4G eMMC

Ethernet:
* Two XFI 10G ports
* Two SGMII ports
* Two RGMII ports

PCIe:
* PCIe1 (SerDes2 Lane0) to miniPCIe slot
* PCIe2 (SerDes2 Lane1) to x2 PCIe slot
* PCIe3 (SerDes2 Lane2) to x4 PCIe slot

SATA:
* SerDes2 Lane3 to SATA port

USB 3.0: one super speed USB 3.0 type A port
one Micro-AB port

UART: supports two UARTs up to 115200 bps for console

Signed-off-by: Mingkai Hu <mingkai.hu@nxp.com>
Signed-off-by: Shaohui Xie <Shaohui.Xie@nxp.com>
Signed-off-by: Gong Qianyu <Qianyu.Gong@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>