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>