genirq/msi: Remove msi_post_free()

The only user of msi_post_free() - powerpc/pseries - has been changed to
use msi_teardown().

Remove this unused callback.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250916061007.964005-1-namcao@linutronix.de

Author: covanam

include/linux/msi.h

@@ -431,8 +431,6 @@ struct msi_domain_info;
  *			function.
  * @domain_free_irqs:	Optional function to override the default free
  *			function.
- * @msi_post_free:	Optional function which is invoked after freeing
- *			all interrupts.
  * @msi_translate:	Optional translate callback to support the odd wire to
  *			MSI bridges, e.g. MBIGEN
  *
@@ -473,8 +471,6 @@ struct msi_domain_ops {
 					     struct device *dev, int nvec);
 	void		(*domain_free_irqs)(struct irq_domain *domain,
 					    struct device *dev);
-	void		(*msi_post_free)(struct irq_domain *domain,
-					 struct device *dev);
 	int		(*msi_translate)(struct irq_domain *domain, struct irq_fwspec *fwspec,
 					 irq_hw_number_t *hwirq, unsigned int *type);
 };

kernel/irq/msi.c

@@ -1644,9 +1644,6 @@ static void msi_domain_free_locked(struct device *dev, struct msi_ctrl *ctrl)
 	else
 		__msi_domain_free_irqs(dev, domain, ctrl);
 
-	if (ops->msi_post_free)
-		ops->msi_post_free(domain, dev);
-
 	if (info->flags & MSI_FLAG_FREE_MSI_DESCS)
 		msi_domain_free_descs(dev, ctrl);
 }