[src][ipc]完善 message queue 相关定义

include/rtthread.h

@@ -378,8 +378,8 @@ rt_mq_t rt_mq_create(const char *name,
                      rt_uint8_t  flag);
 rt_err_t rt_mq_delete(rt_mq_t mq);
 
-rt_err_t rt_mq_send(rt_mq_t mq, void *buffer, rt_size_t size);
-rt_err_t rt_mq_urgent(rt_mq_t mq, void *buffer, rt_size_t size);
+rt_err_t rt_mq_send(rt_mq_t mq, const void *buffer, rt_size_t size);
+rt_err_t rt_mq_urgent(rt_mq_t mq, const void *buffer, rt_size_t size);
 rt_err_t rt_mq_recv(rt_mq_t    mq,
                     void      *buffer,
                     rt_size_t  size,

src/ipc.c

@@ -1960,7 +1960,7 @@ RTM_EXPORT(rt_mq_delete);
  *
  * @return the error code
  */
-rt_err_t rt_mq_send(rt_mq_t mq, void *buffer, rt_size_t size)
+rt_err_t rt_mq_send(rt_mq_t mq, const void *buffer, rt_size_t size)
 {
     register rt_ubase_t temp;
     struct rt_mq_message *msg;
@@ -2050,7 +2050,7 @@ RTM_EXPORT(rt_mq_send);
  *
  * @return the error code
  */
-rt_err_t rt_mq_urgent(rt_mq_t mq, void *buffer, rt_size_t size)
+rt_err_t rt_mq_urgent(rt_mq_t mq, const void *buffer, rt_size_t size)
 {
     register rt_ubase_t temp;
     struct rt_mq_message *msg;