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>

imx: board: Add support for the K+P's kp_imx6q_tpc board

This commit provides support for Kieback & Peter GmbH IMX6Q based
TPC board.

U-boot console output:

U-Boot SPL 2018.05-rc1-00005-g631e2d01fd (Apr 04 2018 - 21:16:24 +0200)
Trying to boot from MMC1

U-Boot 2018.05-rc1-00005-g631e2d01fd (Apr 04 2018 - 21:16:24 +0200)

CPU: Freescale i.MX6Q rev1.5 996 MHz (running at 792 MHz)
CPU: Extended Commercial temperature grade (-20C to 105C) at 37C
Reset cause: POR
Board: K+P KP_IMX6Q_TPC i.MX6Q
Watchdog enabled
I2C: ready
DRAM: 2 GiB
MMC: FSL_SDHC: 0, FSL_SDHC: 1
Loading Environment from MMC... OK
In: serial
Out: serial
Err: serial
Net: FEC [PRIME]
Autoboot in 3 seconds