clk: meson: migrate meson8b out of hw_onecell_data to drop NR_CLKS

The way hw_onecell_data is declared:
struct clk_hw_onecell_data {
	unsigned int num;
	struct clk_hw *hws[];
};

makes it impossible to have the clk_hw table declared outside while
using ARRAY_SIZE() to determine ".num" due to ".hws" being a flexible
array member.

Completely move out of hw_onecell_data and add a custom
devm_of_clk_add_hw_provider() "get" callback to retrieve the clk_hw
in order to finally get rid on the NR_CLKS define.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20230607-topic-amlogic-upstream-clkid-public-migration-v2-5-38172d17c27a@linaro.org


Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>