intel_iommu: Fix shadow local variables on "size"

This patch fixes the warning of shadowed local variable:

../hw/i386/intel_iommu.c: In function ‘vtd_address_space_unmap’:
../hw/i386/intel_iommu.c:3773:18: warning: declaration of ‘size’ shadows a previous local [-Wshadow=compatible-local]
 3773 |         uint64_t size = mask + 1;
      |                  ^~~~
../hw/i386/intel_iommu.c:3747:12: note: shadowed declaration is here
 3747 |     hwaddr size, remain;
      |            ^~~~

Cc: Jason Wang <jasowang@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-ID: <20230922160410.138786-1-peterx@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

hw/i386/intel_iommu.c

@@ -3744,7 +3744,7 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus,
 /* Unmap the whole range in the notifier's scope. */
 static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n)
 {
-    hwaddr size, remain;
+    hwaddr total, remain;
     hwaddr start = n->start;
     hwaddr end = n->end;
     IntelIOMMUState *s = as->iommu_state;
@@ -3765,7 +3765,7 @@ static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n)
     }
 
     assert(start <= end);
-    size = remain = end - start + 1;
+    total = remain = end - start + 1;
 
     while (remain >= VTD_PAGE_SIZE) {
         IOMMUTLBEvent event;
@@ -3793,10 +3793,10 @@ static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n)
     trace_vtd_as_unmap_whole(pci_bus_num(as->bus),
                              VTD_PCI_SLOT(as->devfn),
                              VTD_PCI_FUNC(as->devfn),
-                             n->start, size);
+                             n->start, total);
 
     map.iova = n->start;
-    map.size = size - 1; /* Inclusive */
+    map.size = total - 1; /* Inclusive */
     iova_tree_remove(as->iova_tree, map);
 }