PCI / PM: Use the NEVER_SKIP driver flag

Replace the PCI-specific flag PCI_DEV_FLAGS_NEEDS_RESUME with the
PM core's DPM_FLAG_NEVER_SKIP one everywhere and drop it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>