The dw_plat_pcie_of_match[] forward declaration was required when
dw_plat_pcie_probe() called of_match_device().  5c204204 ("PCI:
designware-plat: Prefer of_device_get_match_data()") replaced that with
of_device_get_match_data(), which no longer needs the declaration.

Drop the unnecessary forward declaration.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20220624143428.8334-19-Sergey.Semin@baikalelectronics.ruTested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>