Documentation: dt: xgene: Add PMD clock binding

Add APM X-Gene clock binding documentation for PMD clock.

Signed-off-by: Hoan Tran <hotran@apm.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

Documentation: Update APM X-Gene clock binding for v2 hardware

Update APM X-Gene clock binding documentation for SoC and
PCP PLL for v2 hardware.

Signed-off-by: Loc Ho <lho@apm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

Documentation: Add documentation for APM X-Gene clock binding

Documentation: Add documentation for APM X-Gene clock binding with PLL and
device clocks.

Signed-off-by: Loc Ho <lho@apm.com>
Signed-off-by: Kumar Sankaran <ksankaran@apm.com>
Signed-off-by: Vinayak Kale <vkale@apm.com>
Signed-off-by: Feng Kan <fkan@apm.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>