PCI: Add pcibios_alloc_irq() and pcibios_free_irq()

Add pcibios_alloc_irq() and pcibios_free_irq(), which are called when
binding/unbinding PCI device drivers.

PCI arch code may implement these to manage IRQ resources for hotplugged
devices.

[bhelgaas: changelog]
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8a0321a..b4832c9 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1645,6 +1645,8 @@
 int pcibios_add_device(struct pci_dev *dev);
 void pcibios_release_device(struct pci_dev *dev);
 void pcibios_penalize_isa_irq(int irq, int active);
+int pcibios_alloc_irq(struct pci_dev *dev);
+void pcibios_free_irq(struct pci_dev *dev);
 
 #ifdef CONFIG_HIBERNATE_CALLBACKS
 extern struct dev_pm_ops pcibios_pm_ops;