ck_hp_fifo: Finer-grained mapping to ck_pr_fence_X_Y.

Specifically, atomic-RMW fences were previously generalized
as store operations.

include/ck_hp_fifo.h

@@ -76,7 +76,7 @@ ck_hp_fifo_enqueue_mpmc(ck_hp_record_t *record,
 
 	entry->value = value;
 	entry->next = NULL;
-	ck_pr_fence_store();
+	ck_pr_fence_store_atomic();
 
 	for (;;) {
 		tail = ck_pr_load_ptr(&fifo->tail);
@@ -93,7 +93,7 @@ ck_hp_fifo_enqueue_mpmc(ck_hp_record_t *record,
 			break;
 	}
 
-	ck_pr_fence_store();
+	ck_pr_fence_atomic();
 	ck_pr_cas_ptr(&fifo->tail, tail, entry);
 	return;
 }
@@ -108,7 +108,7 @@ ck_hp_fifo_tryenqueue_mpmc(ck_hp_record_t *record,
 
 	entry->value = value;
 	entry->next = NULL;
-	ck_pr_fence_store();
+	ck_pr_fence_store_atomic();
 
 	tail = ck_pr_load_ptr(&fifo->tail);
 	ck_hp_set(record, 0, tail);
@@ -123,7 +123,7 @@ ck_hp_fifo_tryenqueue_mpmc(ck_hp_record_t *record,
 	} else if (ck_pr_cas_ptr(&fifo->tail->next, next, entry) == false)
 		return false;
 
-	ck_pr_fence_store();
+	ck_pr_fence_atomic();
 	ck_pr_cas_ptr(&fifo->tail, tail, entry);
 	return true;
 }