To make software license auditing simpler, use SPDX[0] license
identifiers instead of duplicating the license text in every file.

NOTE: Files that have been imported by FreeBSD have not been modified.

[0]: https://spdx.org/

Change-Id: I80a00e1f641b8cc075ca5a95b10607ed9ed8761a
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

Sorry to miss the security configuration for SRAM, if we don't support
it, somebody may modify the comment of SRAM in the non-secure space.
Let's fix this issue.

Signed-off-by: Xing Zheng <zhengxing@rock-chips.com>

The goal is that make clear the secure and SoC codes. Now cleaning them
will help secure code extensions for RK3399 in the future.

Signed-off-by: Xing Zheng <zhengxing@rock-chips.com>