tile PCI RC: gentler warning for missing plug-in PCI

Besides using pr_info() to print the linkdown status for a plug-in
slot, add extra indication that this is expected if the slot is empty.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

arch/tile/include/hv/drv_trio_intf.h

@@ -64,8 +64,9 @@ struct pcie_port_property
    *  will not consider it an error if the link comes up as a x8 link. */
   uint8_t allow_x8: 1;
 
-  /** Reserved. */
-  uint8_t reserved: 1;
+  /** If true, this link is connected to a device which may or may not
+   *  be present. */
+  uint8_t removable: 1;
 
 };
 

arch/tile/kernel/pci_gx.c

@@ -729,8 +729,14 @@ int __init pcibios_init(void)
 			__gxio_mmio_read(trio_context->mmio_base_mac +
 					 reg_offset);
 		if (!port_status.dl_up) {
-			pr_err("PCI: link is down, MAC %d on TRIO %d\n",
-				mac, trio_index);
+			if (pcie_ports[trio_index][mac].removable) {
+				pr_info("PCI: link is down, MAC %d on TRIO %d\n",
+					mac, trio_index);
+				pr_info("This is expected if no PCIe card"
+					" is connected to this link\n");
+			} else
+				pr_err("PCI: link is down, MAC %d on TRIO %d\n",
+					mac, trio_index);
 			continue;
 		}