PCI: Add pci_find_resource()

Add a new helper function pci_find_resource() that can be used to find out
whether a given resource (for example from a child device) is contained
within given PCI device's standard resources.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>