spi: pxa2xx: Drop unneeded '!= 0' comparisons

In the few places it's redundant to compare against 0.
Drop the unneeded comparisons.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210517140351.901-6-andriy.shevchenko@linux.intel.com


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