iommu/amd: Remove domain search for PCI/MSI

Now that the domain can be retrieved through device::msi_domain the domain
search for PCI_MSI[X] is not longer required. Remove it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20200826112334.400700807@linutronix.de

Author: KAGA-KOKO

drivers/iommu/amd/iommu.c

@@ -3562,9 +3562,6 @@ static struct irq_domain *get_irq_domain_for_devid(struct irq_alloc_info *info,
 	case X86_IRQ_ALLOC_TYPE_IOAPIC_GET_PARENT:
 	case X86_IRQ_ALLOC_TYPE_HPET_GET_PARENT:
 		return iommu->ir_domain;
-	case X86_IRQ_ALLOC_TYPE_PCI_MSI:
-	case X86_IRQ_ALLOC_TYPE_PCI_MSIX:
-		return iommu->msi_domain;
 	default:
 		WARN_ON_ONCE(1);
 		return NULL;