nuttx/sched/mqueue: Change 'int prio' to 'unsigned int prio'. According to open group specification, priority field in mq_* functions should have unsigned type: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/mqueue.h.html

drivers/audio/audio_null.c

@@ -424,7 +424,7 @@ static void *null_workerthread(pthread_addr_t pvarg)
   FAR struct null_dev_s *priv = (struct null_dev_s *) pvarg;
   struct audio_msg_s msg;
   int msglen;
-  int prio;
+  unsigned int prio;
 
   audinfo("Entry\n");
 

drivers/audio/cs43l22.c

@@ -1560,7 +1560,7 @@ static void *cs43l22_workerthread(pthread_addr_t pvarg)
   struct audio_msg_s msg;
   FAR struct ap_buffer_s *apb;
   int msglen;
-  int prio;
+  unsigned int prio;
 
   audinfo("Entry\n");
 

drivers/audio/vs1053.c

@@ -1248,7 +1248,7 @@ static void *vs1053_workerthread(pthread_addr_t pvarg)
   struct audio_msg_s      msg;
   FAR struct ap_buffer_s *apb;
   int                     size;
-  int                     prio;
+  unsigned int            prio;
 #ifndef CONFIG_AUDIO_EXCLUDE_STOP
   uint16_t                reg;
 #endif

drivers/audio/wm8776.c

@@ -1151,7 +1151,7 @@ static void *wm8776_workerthread(pthread_addr_t pvarg)
   struct audio_msg_s msg;
   FAR struct ap_buffer_s *apb;
   int msglen;
-  int prio;
+  unsigned int prio;
   struct mq_attr attr;
 
   audinfo("Entry\n");

drivers/audio/wm8904.c

@@ -2006,7 +2006,7 @@ static void *wm8904_workerthread(pthread_addr_t pvarg)
   struct audio_msg_s msg;
   FAR struct ap_buffer_s *apb;
   int msglen;
-  int prio;
+  unsigned int prio;
 
   audinfo("Entry\n");