PCI/MSI: Kill msi_controller structure

msi_controller had a good, long life as the abstraction for
a driver providing MSIs to PCI devices. But it has been replaced
in all drivers by the more expressive generic MSI framework.

Farewell, struct msi_controller.

Link: https://lore.kernel.org/r/20210330151145.997953-9-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>

Author: Marc Zyngier

include/linux/msi.h

@@ -240,8 +240,7 @@ void pci_msi_unmask_irq(struct irq_data *data);
 /*
  * The arch hooks to setup up msi irqs. Default functions are implemented
  * as weak symbols so that they /can/ be overriden by architecture specific
- * code if needed. These hooks must be enabled by the architecture or by
- * drivers which depend on them via msi_controller based MSI handling.
+ * code if needed. These hooks can only be enabled by the architecture.
  *
  * If CONFIG_PCI_MSI_ARCH_FALLBACKS is not selected they are replaced by
  * stubs with warnings.
@@ -272,19 +271,6 @@ static inline void arch_teardown_msi_irqs(struct pci_dev *dev)
 void arch_restore_msi_irqs(struct pci_dev *dev);
 void default_restore_msi_irqs(struct pci_dev *dev);
 
-struct msi_controller {
-	struct module *owner;
-	struct device *dev;
-	struct device_node *of_node;
-	struct list_head list;
-
-	int (*setup_irq)(struct msi_controller *chip, struct pci_dev *dev,
-			 struct msi_desc *desc);
-	int (*setup_irqs)(struct msi_controller *chip, struct pci_dev *dev,
-			  int nvec, int type);
-	void (*teardown_irq)(struct msi_controller *chip, unsigned int irq);
-};
-
 #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
 
 #include <linux/irqhandler.h>