spi: pxa2xx: Fix printf() specifiers

Instead of explicit casting use proper specifier in one case,
and fix specifier signness in another.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210517140351.901-7-andriy.shevchenko@linux.intel.com


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