spi: pxa2xx: Validate the correctness of the SSP type

Currently we blindly apply the SSP type value from any source of the
information. Increase robustness by validating the value before use.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221021190018.63646-2-andriy.shevchenko@linux.intel.com


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