7127  remove -Wno-missing-braces from Makefile.uts

@@ -70,11 +70,11 @@
 
 static taskq_t *xbuf_tq = NULL;
 static int xbuf_attr_tq_minalloc = XBUF_TQ_MINALLOC;
 static int xbuf_attr_tq_maxalloc = XBUF_TQ_MAXALLOC;
 
-static kmutex_t xbuf_mutex = { 0 };
+static kmutex_t xbuf_mutex = { {NULL} };
 static uint32_t xbuf_refcount = 0;
 
 /*
  * Private wrapper for buf cloned via ddi_xbuf_qstrategy()
  */