clk: migrate to SPDX-License-Identifier use ...

Some of these are a product of source sync with Linux, the other were
done with macro assistance by searching for /later/, deleting license text,
adding appropriate SPDX-License-Identifier and manual post-review.

Devices without a license indicated where assumed GPL-2.0-only according
with the project's license.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: Add Layerscape clk support ...

This adds support for the clock controller found on Layerscape
SoCs. This is mostly an adoption of the corresponding Linux
driver. This is tested on the LS1046a SoC. Other ARM based Layerscape
SoCs should work aswell, support for the PowerPC based SoCs has
been removed.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>