Canonically include stack/gatt::

Bug: 183374320
Test: gd/cert/run
Tag: #refactor

Change-Id: I5bb782f3d019535cd53129cfe450bb233c912975
diff --git a/stack/gatt/gatt_sr.cc b/stack/gatt/gatt_sr.cc
index e637eb2..c0aedfa 100644
--- a/stack/gatt/gatt_sr.cc
+++ b/stack/gatt/gatt_sr.cc
@@ -28,9 +28,9 @@
 
 #include "gatt_int.h"
 #include "l2c_api.h"
-#include "l2c_int.h"
 #include "osi/include/log.h"
 #include "stack/eatt/eatt.h"
+#include "stack/l2cap/l2c_int.h"
 #define GATT_MTU_REQ_MIN_LEN 2
 
 using base::StringPrintf;