PCI/PTM: Remove error message at boot

Since 39850ed ("PCI/PTM: Save/restore Precision Time Measurement
Capability for suspend/resume"), devices that have PTM capability but
don't enable it see this message on calls to pci_save_state():

  no suspend buffer for PTM

Drop the message, it's perfectly fine not to use a capability.

Fixes: 39850ed ("PCI/PTM: Save/restore Precision Time Measurement Capability for suspend/resume")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Acked-by: David E. Box <[email protected]>

drivers/pci/pcie/ptm.c

@@ -60,10 +60,8 @@ void pci_save_ptm_state(struct pci_dev *dev)
 		return;
 
 	save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_PTM);
-	if (!save_state) {
-		pci_err(dev, "no suspend buffer for PTM\n");
+	if (!save_state)
 		return;
-	}
 
 	cap = (u16 *)&save_state->cap.data[0];
 	pci_read_config_word(dev, ptm + PCI_PTM_CTRL, cap);