PCI: Make pci_bus_attrs, pci_dev_attrs, dev_rescan_attr, dev_remove_attr, vga_attr static

Local variables used only in this file are made static.

[bhelgaas: also make pci_dev_attrs[] static (from Fengguang)]
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>