genirq/msi: Populate sysfs entry only once

The MSI entries for multi-MSI are populated en bloc for the MSI descriptor,
but the current code invokes the population inside the per interrupt loop
which triggers a warning in the sysfs code and causes the interrupt
allocation to fail.

Move it outside of the loop so it works correctly for single and multi-MSI.

Fixes: bf5e758f ("genirq/msi: Simplify sysfs handling")
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/87leznqx2a.ffs@tglx

kernel/irq/msi.c

@@ -887,12 +887,11 @@ int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 			ret = msi_init_virq(domain, virq + i, vflags);
 			if (ret)
 				return ret;
-
-			if (info->flags & MSI_FLAG_DEV_SYSFS) {
-				ret = msi_sysfs_populate_desc(dev, desc);
-				if (ret)
-					return ret;
-			}
+		}
+		if (info->flags & MSI_FLAG_DEV_SYSFS) {
+			ret = msi_sysfs_populate_desc(dev, desc);
+			if (ret)
+				return ret;
 		}
 		allocated++;
 	}