VT-d: replace bogus gprintk()

Just like the other messages in this function this one should be issued
through plain printk() - the current vCPU is irrelevant here. (Noticed
while backporting to older trees, which don't have gprintk().)

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -858,8 +858,8 @@ static int iommu_page_fault_do_one(struc
         break;
     }
 
-    gprintk(XENLOG_G_WARNING VTDPREFIX, "%s: reason %02x - %s\n",
-            kind, fault_reason, reason);
+    printk(XENLOG_G_WARNING VTDPREFIX "%s: reason %02x - %s\n",
+           kind, fault_reason, reason);
 
     if ( iommu_verbose && fault_type == DMA_REMAP )
         print_vtd_entries(iommu, PCI_BUS(source_id), PCI_DEVFN2(source_id),