spi: pxa2xx-pci: Drop redundant NULL check in ->probe()

Since all platforms are using ->setup() function, drop unneeded check.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220225172350.69797-3-andriy.shevchenko@linux.intel.com


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