PCI: Remove unnecessary header includes

Remove unnecessary includes of:

  linux/of_pci.h
  linux/pci-ats.h
  asm/setup.h

CoverityScan CID 16442, 16443, 16444 ("Unnecessary header file (HFA)")

Link: https://lore.kernel.org/r/eba4c0f2b35b1442773a722f1cf73f7240f818e3.1597325845.git.gustavo.pimentel@synopsys.com
Link: https://lore.kernel.org/r/72ade1f5af35b994a7a8216ea5dc32c27cf134cd.1597325845.git.gustavo.pimentel@synopsys.com
Link: https://lore.kernel.org/r/715821dc855add2565505ff8dcb9970e87996c5c.1597325845.git.gustavo.pimentel@synopsys.com
[bhelgaas: squash]
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Joao Pinto <jpinto@synopsys.com>