'clocks' in the example is not parsable with the 0 phandle value
because the number of #clock-cells is unknown in the previous entry.
Solve this by adding the clock provider node. Only 'cpg_clocks' is
needed as the examples are built with fixups which can be used to
identify phandles.

This is in preparation to support schema validation on .dtb files.
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220301190400.1644150-1-robh@kernel.orgAcked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>