treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

clk: add artpec-6 clock controller

Add a driver for the main clock controller of the Artpec-6 Soc.

Signed-off-by: Lars Persson <larper@axis.com>
[sboyd@codeaurora.org: Reformatted driver structure and of match]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>