spi: pxa2xx: Don't provide struct chip_data for others

Now the struct chip_data is local to spi-pxa2xx.c, move
its definition to the C file. This will slightly speed up
a build and also hide badly named data type (too generic).

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240417110334.2671228-10-andriy.shevchenko@linux.intel.com


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