ACPI / bind: Rework struct acpi_bus_type

Replace the .find_device function pointer in struct acpi_bus_type
with a new one, .find_companion, that is supposed to point to a
function returning struct acpi_device pointer (instead of an int)
and takes one argument (instead of two).  This way the role of
this callback is more clear and the implementation of it can
be more straightforward.

Update all of the users of struct acpi_bus_type (PCI, PNP/ACPI and
USB) to reflect the structure change.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Lan Tianyu <tianyu.lan@intel.com> # for USB/ACPI
ACPI / bind: Pass struct acpi_device pointer to acpi_bind_one()

There is no reason to pass an ACPI handle to acpi_bind_one() instead
of a struct acpi_device pointer to the target device object, so
modify that function to take a struct acpi_device pointer as its
second argument and update all code depending on it accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Lan Tianyu <tianyu.lan@intel.com> # for USB/ACPI
ACPI / bind: Move acpi_get_child() to drivers/ide/ide-acpi.c

Since drivers/ide/ide-acpi.c is the only remaining user of
acpi_get_child(), move that function into that file as a static
routine.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'acpi-hotplug-next' into bleeding-edge

* acpi-hotplug-next:
  ACPI / bind: Move acpi_get_child() to drivers/ide/ide-acpi.c
  ACPI / bind: Pass struct acpi_device pointer to acpi_bind_one()
  ACPI / bind: Rework struct acpi_bus_type