PCI_DEV_FLAGS_NO_D3 should not be used outside of PCI core.

Instead, we can use pci_save_state() to hint PCI core that the device
should stay at D0 during suspend. By doing so, PCI core will let the
upstream bridges also stays at D0 so the entire hierarchy is in the
correct power state as PCI spec mandates.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>