memory: Move FlatView allocation to a helper

This moves a FlatView allocation and initialization to a helper.
While we are nere, replace g_new with g_new0 to not to bother if we add
new fields in the future.

This should cause no behavioural change.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Message-Id: <20170921085110.25598-4-aik@ozlabs.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

memory.c

@@ -258,12 +258,14 @@ static bool flatrange_equal(FlatRange *a, FlatRange *b)
         && a->readonly == b->readonly;
 }
 
-static void flatview_init(FlatView *view)
+static FlatView *flatview_new(void)
 {
+    FlatView *view;
+
+    view = g_new0(FlatView, 1);
     view->ref = 1;
-    view->ranges = NULL;
-    view->nr = 0;
-    view->nr_allocated = 0;
+
+    return view;
 }
 
 /* Insert a range into a given position.  Caller is responsible for maintaining
@@ -707,8 +709,7 @@ static FlatView *generate_memory_topology(MemoryRegion *mr)
 {
     FlatView *view;
 
-    view = g_new(FlatView, 1);
-    flatview_init(view);
+    view = flatview_new();
 
     if (mr) {
         render_memory_region(view, mr, int128_zero(),
@@ -2629,8 +2630,7 @@ void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name)
     as->ref_count = 1;
     as->root = root;
     as->malloced = false;
-    as->current_map = g_new(FlatView, 1);
-    flatview_init(as->current_map);
+    as->current_map = flatview_new();
     as->ioeventfd_nb = 0;
     as->ioeventfds = NULL;
     QTAILQ_INIT(&as->listeners);