clk: berlin: add berlin clocks DT bindings documentation

Document the device tree bindings for the PLLs found on the Marvell Berlin SoCs.

Cc: devicetree@vger.kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
ARM: berlin/dt: add cpupll and syspll support to BG2Q

The Berlin BG2Q has two supported PLLs: CPU PLL and System PLL, add those to the
SoC device tree.

Note that support for the AVPLL is not yet available.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
ARM: berlin/dt: add cpupll and syspll support to BG2CD

The Berlin BG2CD has two supported PLLs: CPU PLL and System PLL, add those to
the SoC device tree.

This also moves the remaining clocks from the clocks container node to the root.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
ARM: berlin/dt: add cpupll and syspll support to BG2

The Berlin BG2 has two supported PLLs: CPU PLL and System PLL, add those to the
SoC device tree.

This also moves the remaining clocks from the clocks container node to the root.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>