leds: pca955x: Refactor with helper functions and renaming

Add helper functions to clean up the code, and rename a few
oddly named functions and variables.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20250212143038.1416501-2-eajames@linux.ibm.com


Signed-off-by: Lee Jones <lee@kernel.org>