mailbox: bcm-flexrm-mailbox: Rework MSI interrupt handling

No point in retrieving the MSI descriptors. Just query the Linux interrupt
number.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211210221815.148331680@linutronix.de

drivers/mailbox/bcm-flexrm-mailbox.c

@@ -1497,7 +1497,6 @@ static int flexrm_mbox_probe(struct platform_device *pdev)
 	int index, ret = 0;
 	void __iomem *regs;
 	void __iomem *regs_end;
-	struct msi_desc *desc;
 	struct resource *iomem;
 	struct flexrm_ring *ring;
 	struct flexrm_mbox *mbox;
@@ -1608,10 +1607,8 @@ static int flexrm_mbox_probe(struct platform_device *pdev)
 		goto fail_destroy_cmpl_pool;
 
 	/* Save alloced IRQ numbers for each ring */
-	for_each_msi_entry(desc, dev) {
-		ring = &mbox->rings[desc->msi_index];
-		ring->irq = desc->irq;
-	}
+	for (index = 0; index < mbox->num_rings; index++)
+		mbox->rings[index].irq = msi_get_virq(dev, index);
 
 	/* Check availability of debugfs */
 	if (!debugfs_initialized())