clk: at91: update to PMC bindings ...

Based on kernel 5.0-rc6 update at91 clk support
to match the new PMC bindings.

Manually added all changes done in the kernel from 4.9-rc3 to 5.0-rc6.
New drivers required was added as seperate commits.

This includes dt-compat code required to support at91sam5d3,
as this is not yet ported to use the new PMC bindings.

clk-programmable saw some extra changes - it had never been bulit.
It is used only by at91sama5d2 - and barebox has no board support for
this cpu (yet).

The CONFIG_SOC symbols is used to select the relevant drivers.
CONFIG_SOC_SAM9 selects several drivers, and in the future
this can be split to keep the image size down.

In the kernel CLK_OF_DECLARE_DRIVER() can be used for a two step init.
In barebox this is a simple one step init.
It was added to have less differences between the kernel and the barebox
versions of the drivers.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Tested-by: Ladislav Michl <ladis@linux-mips.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>