genirq/msi: Remove unused domain callbacks

No users and there is no need to grow them.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211126223824.322987915@linutronix.de
Link: https://lore.kernel.org/r/20211206210224.041777889@linutronix.de

include/linux/msi.h

@@ -304,7 +304,6 @@ struct msi_domain_info;
  * @msi_free:		Domain specific function to free a MSI interrupts
  * @msi_check:		Callback for verification of the domain/info/dev data
  * @msi_prepare:	Prepare the allocation of the interrupts in the domain
- * @msi_finish:		Optional callback to finalize the allocation
  * @set_desc:		Set the msi descriptor for an interrupt
  * @handle_error:	Optional error handler if the allocation fails
  * @domain_alloc_irqs:	Optional function to override the default allocation
@@ -312,12 +311,11 @@ struct msi_domain_info;
  * @domain_free_irqs:	Optional function to override the default free
  *			function.
  *
- * @get_hwirq, @msi_init and @msi_free are callbacks used by
- * msi_create_irq_domain() and related interfaces
+ * @get_hwirq, @msi_init and @msi_free are callbacks used by the underlying
+ * irqdomain.
  *
- * @msi_check, @msi_prepare, @msi_finish, @set_desc and @handle_error
- * are callbacks used by msi_domain_alloc_irqs() and related
- * interfaces which are based on msi_desc.
+ * @msi_check, @msi_prepare, @handle_error and @set_desc are callbacks used by
+ * msi_domain_alloc/free_irqs().
  *
  * @domain_alloc_irqs, @domain_free_irqs can be used to override the
  * default allocation/free functions (__msi_domain_alloc/free_irqs). This
@@ -351,7 +349,6 @@ struct msi_domain_ops {
 	int		(*msi_prepare)(struct irq_domain *domain,
 				       struct device *dev, int nvec,
 				       msi_alloc_info_t *arg);
-	void		(*msi_finish)(msi_alloc_info_t *arg, int retval);
 	void		(*set_desc)(msi_alloc_info_t *arg,
 				    struct msi_desc *desc);
 	int		(*handle_error)(struct irq_domain *domain,

kernel/irq/msi.c

@@ -562,8 +562,6 @@ int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 			ret = -ENOSPC;
 			if (ops->handle_error)
 				ret = ops->handle_error(domain, desc, ret);
-			if (ops->msi_finish)
-				ops->msi_finish(&arg, ret);
 			return ret;
 		}
 
@@ -573,9 +571,6 @@ int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 		}
 	}
 
-	if (ops->msi_finish)
-		ops->msi_finish(&arg, 0);
-
 	can_reserve = msi_check_reservation_mode(domain, info, dev);
 
 	/*