xhci: Remove warnings about MSI and MSI-X capabilities.

xHCI host controllers may not be capable of MSI, but they should be able
to be used in legacy PCI interrupt mode.  Similarly, some xHCI host
controllers will have MSI support but not MSI-X support.  Lower the
dmesg log level from an error to debug.  The message won't appear unless
CONFIG_USB_XHCI_HCD_DEBUGGING is turned on.

If we need to find out whether the device can support MSI or MSI-X and
it's not being enabled by the driver, it's easy to ask the user to run
lspci.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

drivers/usb/host/xhci.c

@@ -200,14 +200,14 @@ static int xhci_setup_msi(struct xhci_hcd *xhci)
 
 	ret = pci_enable_msi(pdev);
 	if (ret) {
-		xhci_err(xhci, "failed to allocate MSI entry\n");
+		xhci_dbg(xhci, "failed to allocate MSI entry\n");
 		return ret;
 	}
 
 	ret = request_irq(pdev->irq, (irq_handler_t)xhci_msi_irq,
 				0, "xhci_hcd", xhci_to_hcd(xhci));
 	if (ret) {
-		xhci_err(xhci, "disable MSI interrupt\n");
+		xhci_dbg(xhci, "disable MSI interrupt\n");
 		pci_disable_msi(pdev);
 	}
 
@@ -270,7 +270,7 @@ static int xhci_setup_msix(struct xhci_hcd *xhci)
 
 	ret = pci_enable_msix(pdev, xhci->msix_entries, xhci->msix_count);
 	if (ret) {
-		xhci_err(xhci, "Failed to enable MSI-X\n");
+		xhci_dbg(xhci, "Failed to enable MSI-X\n");
 		goto free_entries;
 	}
 
@@ -286,7 +286,7 @@ static int xhci_setup_msix(struct xhci_hcd *xhci)
 	return ret;
 
 disable_msix:
-	xhci_err(xhci, "disable MSI-X interrupt\n");
+	xhci_dbg(xhci, "disable MSI-X interrupt\n");
 	xhci_free_irq(xhci);
 	pci_disable_msix(pdev);
 free_entries: