[PATCH for-4.20? 1/3] AMD/IOMMU: drop stray MSI enabling

[Jan Beulich <jbeulich@suse.com>]

While the 2nd of the commits referenced below should have moved the call
to amd_iommu_msi_enable() instead of adding another one, the situation
wasn't quite right even before: It can't have done any good to enable
MSI when no IRQ was allocated for it, yet.

Fixes: 5f569f1ac50e ("AMD/IOMMU: allow enabling with IRQ not yet set up")
Fixes: d9e49d1afe2e ("AMD/IOMMU: adjust setup of internal interrupt for x2APIC mode")
Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/drivers/passthrough/amd/iommu_init.c
+++ b/xen/drivers/passthrough/amd/iommu_init.c
@@ -902,8 +902,6 @@ static void enable_iommu(struct amd_iomm
         }
     }
 
-    amd_iommu_msi_enable(iommu, IOMMU_CONTROL_ENABLED);
-
     set_iommu_ht_flags(iommu);
     set_iommu_command_buffer_control(iommu, IOMMU_CONTROL_ENABLED);