PCI: Warn about failures instead of "must_check" functions

These places capture return values to avoid "must_check" warnings,
but we didn't *do* anything with the return values, which causes
"set but not used" warnings.  We might as well do something instead
of just trying to evade the "must_check" warnings.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/setup-bus.c

@@ -1545,6 +1545,8 @@ again:
 
 enable_all:
 	retval = pci_reenable_device(bridge);
+	if (retval)
+		dev_err(&bridge->dev, "Error reenabling bridge (%d)\n", retval);
 	pci_set_master(bridge);
 	pci_enable_bridges(parent);
 }