cmdu_ackq: remove unused mutex variable

src/cmdu_ackq.h

@@ -22,7 +22,6 @@
 #define MAC_ADDR_HASH(a)	(a[0] ^ a[1] ^ a[2] ^ a[3] ^ a[4] ^ a[5])
 #endif
 
-// TODO: improve hash func
 #define cmdu_ackq_hash(t, m, o)		\
 	((MAC_ADDR_HASH(o) ^ (t) ^ (m)) & (CMDU_BACKLOG_MAX - 1))
 
@@ -45,8 +44,6 @@ struct cmdu_ackq_entry {
 
 /* queue of cmdus for which response is pending */
 struct cmdu_ackq {
-	pthread_mutex_t qlock;
-
 	/* hashtable of pending cmdu_ackq_entry */
 	struct hlist_head table[CMDU_BACKLOG_MAX];