gnttab: Remove unused per-domain map_count field

Signed-off-by: Steven Smith <steven.smith@eu.citrix.com>

xen/common/grant_table.c

@@ -119,7 +119,6 @@ __get_maptrack_handle(
     if ( unlikely((h = t->maptrack_head) == (t->maptrack_limit - 1)) )
         return -1;
     t->maptrack_head = maptrack_entry(t, h).ref;
-    t->map_count++;
     return h;
 }
 
@@ -129,7 +128,6 @@ put_maptrack_handle(
 {
     maptrack_entry(t, handle).ref = t->maptrack_head;
     t->maptrack_head = handle;
-    t->map_count--;
 }
 
 static inline int

xen/include/xen/grant_table.h

@@ -91,7 +91,6 @@ struct grant_table {
     struct grant_mapping **maptrack;
     unsigned int          maptrack_head;
     unsigned int          maptrack_limit;
-    unsigned int          map_count;
     /* Lock protecting updates to active and shared grant tables. */
     spinlock_t            lock;
 };