gpio: rdc321x: Convert PCIBIOS_* return codes to errnos

gpio: rdc321x: Convert PCIBIOS_* return codes to errnos

rdc_gpio_config() uses pci_{read,write}_config_dword() that return
PCIBIOS_* codes. rdc_gpio_config() is used for
direction_{input,output}() in the struct gpio_chip which both require
normal errnos to be returned.

Similarly, rdc321x_gpio_probe() that is probe function returns
PCIBIOS_* codes without converting them first into normal errnos.

Convert PCIBIOS_* returns code using pcibios_err_to_errno() into normal
errno before returning them to fix both issues.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240527132345.13956-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>