PCI: aardvark: Remove unused of_gpio.h inclusion

The of_gpio.h API is deprecated and subject to removal. The driver doesn't
use it, so simply remove the unused header.

[kwilczynski: commit log]
Link: https://lore.kernel.org/linux-pci/20240506142142.4042810-3-andriy.shevchenko@linux.intel.com


Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>