PCI/ACPI: Pass acpi_pci_root to acpi_pci_drivers' add/remove interface

This patch changes .add/.remove interfaces of acpi_pci_driver.
In the current implementation acpi_handle is passed as a parameter
of .add/.remove interface.  However, the acpi_pci_root structure
contains more useful information than just the acpi_handle.  This
enables us to avoid some useless lookups in each acpi_pci_driver.

Note: This changes interfaces used by acpi_pci_register_driver(), an
exported symbol.  This patch updates all the in-kernel users, but any
out-of-kernel acpi_pci_register_driver() users will need updates.

[bhelgaas: changelog]
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>