ASoC: nau8825: Change Tegra clk_out_2 provider to PMC

Tegra clk_out_1, clk_out_2, and clk_out_3 are part of PMC block and
these clocks are moved from the clock driver to PMC driver with PMC as
a provider for these clocks.

Update bindings document to use PMC as clock provider for clk_out_2 and
change ID to PMC clock ID.

Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>