spi: pxa2xx: Introduce temporary variables to increase readability

The current conditional for PCI ID matching is hard to read.
Introduce couple of temporary variables to increase readability
of the code.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20191021103625.4250-1-andriy.shevchenko@linux.intel.com


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