memory: Use canonical path component as the name

Rather than having the name as separate state. This prepares support
for creating a MemoryRegion dynamically (i.e. without
memory_region_init() and friends) and the MemoryRegion still getting
a usable name.
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

include/exec/memory.h

@@ -162,7 +162,6 @@ struct MemoryRegion {
     QTAILQ_HEAD(subregions, MemoryRegion) subregions;
     QTAILQ_ENTRY(MemoryRegion) subregions_link;
     QTAILQ_HEAD(coalesced_ranges, CoalescedMemoryRange) coalesced;
-    const char *name;
     uint8_t dirty_log_mask;
     unsigned ioeventfd_nb;
     MemoryRegionIoeventfd *ioeventfds;

memory.c

@@ -915,7 +915,6 @@ void memory_region_init(MemoryRegion *mr,
     if (size == UINT64_MAX) {
         mr->size = int128_2_64();
     }
-    mr->name = g_strdup(name);
 
     if (name) {
         object_property_add_child_array(owner, name, OBJECT(mr));
@@ -1260,7 +1259,6 @@ static void memory_region_finalize(Object *obj)
     assert(memory_region_transaction_depth == 0);
     mr->destructor(mr);
     memory_region_clear_coalescing(mr);
-    g_free((char *)mr->name);
     g_free(mr->ioeventfds);
 }
 
@@ -1310,7 +1308,7 @@ uint64_t memory_region_size(MemoryRegion *mr)
 
 const char *memory_region_name(const MemoryRegion *mr)
 {
-    return mr->name;
+    return object_get_canonical_path_component(OBJECT(mr));
 }
 
 bool memory_region_is_ram(MemoryRegion *mr)