spi: pxa2xx-pci: Refactor CE4100 to use ->setup()

Refactor CE4100 handling code to use ->setup() instead of spreading
potentially confusing conditional.

Besides that, it will allow to refactor further to avoid intermediate
storage for the used configuration parameters.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220225172350.69797-1-andriy.shevchenko@linux.intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>