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: zynqmp: rename driver specific CLK_MUX_READ_ONLY ...

Since commit c7cc27d006cc (clk: mux: Support CLK_MUX_READ_ONLY flag)
Barebox defines the CLK_MUX_READ_ONLY flag like Linux.

The ZynqMP clock driver used the flag before, because this flag is used
to convey this information from the PMU firmware to the Linux driver.
However, the flags of the common clock framework and the flag of the
protocol between PMU firmware and the ZynqMP clock driver should be
handled separately.

Therefore, add a driver specific prefix to the flag definition in the
ZynqMP driver.

Fixes the warning

	drivers/clk/zynqmp/clk-mux-zynqmp.c:18:0: warning: "CLK_MUX_READ_ONLY" redefined
	In file included from drivers/clk/zynqmp/clk-mux-zynqmp.c:13:0:
	include/linux/clk.h:350:0: note: this is the location of the previous definition

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

clk: add ZynqMP clock driver ...

The ZynqMP has a platform management unit (PMU) that is responsible for
managing the clocks. Therefore, the clock driver uses the firmware
driver to control the clocks.

The Barebox driver is based on the Linux driver, but contains deviations
to make the driver more readable and more consistent.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>