clk: fixed-factor: add fwname-based constructor functions

clk: fixed-factor: add fwname-based constructor functions

Add four functions to register clk_hw based on the fw_name field in
clk_parent_data, ie the value in the DT property `clock-names`.

There are variants for devm or not and passing an accuracy or not
passing one:

 - clk_hw_register_fixed_factor_fwname
 - clk_hw_register_fixed_factor_with_accuracy_fwname
 - devm_clk_hw_register_fixed_factor_fwname
 - devm_clk_hw_register_fixed_factor_with_accuracy_fwname

The `struct clk_parent_data` init is extracted from
__clk_hw_register_fixed_factor to each calling function. It is required
to allow each function to pass whatever field they want, not only index.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://lore.kernel.org/r/20240221-mbly-clk-v7-2-31d4ce3630c3@bootlin.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>