clk: asm9260: use parent index to link the reference clock

Rewrite clk-asm9260 to use parent index to use the reference clock.
During this rework two helpers are added:

- clk_hw_register_mux_table_parent_data() to supplement
  clk_hw_register_mux_table() but using parent_data instead of
  parent_names

- clk_hw_register_fixed_rate_parent_accuracy() to be used instead of
  directly calling __clk_hw_register_fixed_rate(). The later function is
  an internal API, which is better not to be called directly.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220916061740.87167-2-dmitry.baryshkov@linaro.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>