mm/kasan: fix wanring expression result unused

nuttx/mm/mm_heap/mm_malloc_size.c:77:16: error: expression result unused [-Werror,-Wunused-value]
  kasan_bypass(flag);
               ^~~~
Signed-off-by: buxiasen <buxiasen@xiaomi.com>

include/nuttx/mm/kasan.h

@@ -48,7 +48,7 @@
 #  define kasan_stop()
 #  define kasan_debugpoint(t,a,s) 0
 #  define kasan_init_early()
-#  define kasan_bypass(state) (state)
+#  define kasan_bypass(state) false
 #else
 
 #  define kasan_init_early() kasan_stop()

mm/mm_heap/mm_malloc_size.c

@@ -75,5 +75,6 @@ size_t mm_malloc_size(FAR struct mm_heap_s *heap, FAR void *mem)
   size = MM_SIZEOF_NODE(node) - MM_ALLOCNODE_OVERHEAD;
 
   kasan_bypass(flag);
+  UNUSED(flag);
   return size;
 }