PCI: Init PCIe feature bits for managed host bridge alloc

Two functions allocate a host bridge: devm_pci_alloc_host_bridge() and
pci_alloc_host_bridge().  At the moment, only the unmanaged one initializes
the PCIe feature bits, which prevents from using features such as hotplug
or AER on some systems, when booting with device tree.  Make the
initialization code common.

Fixes: 02bfeb4842 ("PCI/portdrv: Simplify PCIe feature permission checking")
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org	# v4.17+

drivers/pci/probe.c

@@ -586,16 +586,9 @@ static void pci_release_host_bridge_dev(struct device *dev)
 	kfree(to_pci_host_bridge(dev));
 }
 
-struct pci_host_bridge *pci_alloc_host_bridge(size_t priv)
+static void pci_init_host_bridge(struct pci_host_bridge *bridge)
 {
-	struct pci_host_bridge *bridge;
-
-	bridge = kzalloc(sizeof(*bridge) + priv, GFP_KERNEL);
-	if (!bridge)
-		return NULL;
-
 	INIT_LIST_HEAD(&bridge->windows);
-	bridge->dev.release = pci_release_host_bridge_dev;
 
 	/*
 	 * We assume we can manage these PCIe features.  Some systems may
@@ -608,6 +601,18 @@ struct pci_host_bridge *pci_alloc_host_bridge(size_t priv)
 	bridge->native_shpc_hotplug = 1;
 	bridge->native_pme = 1;
 	bridge->native_ltr = 1;
+}
+
+struct pci_host_bridge *pci_alloc_host_bridge(size_t priv)
+{
+	struct pci_host_bridge *bridge;
+
+	bridge = kzalloc(sizeof(*bridge) + priv, GFP_KERNEL);
+	if (!bridge)
+		return NULL;
+
+	pci_init_host_bridge(bridge);
+	bridge->dev.release = pci_release_host_bridge_dev;
 
 	return bridge;
 }
@@ -622,7 +627,7 @@ struct pci_host_bridge *devm_pci_alloc_host_bridge(struct device *dev,
 	if (!bridge)
 		return NULL;
 
-	INIT_LIST_HEAD(&bridge->windows);
+	pci_init_host_bridge(bridge);
 	bridge->dev.release = devm_pci_release_host_bridge_dev;
 
 	return bridge;