Add X-Gene PMD clock support.

PMD clock is implemented for a single register field.
  Output rate = parent_rate * (denominator - scale) / denominator
with
  - denominator = bitmask of register field + 1
  - scale = value of register field

For example, for bitmask is 0x7, denominator will be 8 and scale
will be computed and programmed accordingly.

v2
 * Imply clock shift and width by the compatible string as Rob's comments

v1
 * Initial

Hoan Tran (3):
  Documentation: dtb: xgene: Add PMD clock binding
  clk: xgene: Add PMD clock
  arm64: dts: xgene: Add DT node for APM X-Gene 2 CPU clocks

 Documentation/devicetree/bindings/clock/xgene.txt |  18 ++
 arch/arm64/boot/dts/apm/apm-shadowcat.dtsi        |  56 ++++++
 drivers/clk/clk-xgene.c                           | 221 ++++++++++++++++++++++
 3 files changed, 295 insertions(+)

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1.9.1