Minor fixes

- Include <mutex> for heart_rate_server
- Remove unnecessary assignment

Test: Build
Change-Id: Ic2368d08789b95e71c083460148c70b9d0ef0b20
diff --git a/service/example/heart_rate/heart_rate_server.h b/service/example/heart_rate/heart_rate_server.h
index c7df8a1..5f64d85 100644
--- a/service/example/heart_rate/heart_rate_server.h
+++ b/service/example/heart_rate/heart_rate_server.h
@@ -16,6 +16,7 @@
 
 #pragma once
 
+#include <mutex>
 #include <unordered_map>
 
 #include <base/macros.h>
diff --git a/stack/avrc/avrc_bld_ct.cc b/stack/avrc/avrc_bld_ct.cc
index 6e36421..2cb1246 100644
--- a/stack/avrc/avrc_bld_ct.cc
+++ b/stack/avrc/avrc_bld_ct.cc
@@ -475,7 +475,7 @@
   AVRC_TRACE_API("%s", __func__);
   /* get the existing length, if any, and also the num attributes */
   uint8_t* p_start = (uint8_t*)(p_pkt + 1) + p_pkt->offset;
-  uint8_t* p_data = p_data = p_start + 2; /* pdu + rsvd */
+  uint8_t* p_data = p_start + 2; /* pdu + rsvd */
 
   /* To change addressed player the following is the total length:
    * Player ID (2)