libnvpair: fix unused, remove argsused

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12844

module/nvpair/nvpair.c

@@ -576,6 +576,7 @@ nvlist_nv_alloc(int kmflag)
 		return (nv_alloc_pushpage);
 	}
 #else
+	(void) kmflag;
 	return (nv_alloc_nosleep);
 #endif /* _KERNEL */
 }
@@ -2296,10 +2297,11 @@ nvlist_add_nvpair(nvlist_t *nvl, nvpair_t *nvp)
  * the values are taken from nvl in the case of duplicates.
  * Return 0 on success.
  */
-/*ARGSUSED*/
 int
 nvlist_merge(nvlist_t *dst, nvlist_t *nvl, int flag)
 {
+	(void) flag;
+
 	if (nvl == NULL || dst == NULL)
 		return (EINVAL);
 
@@ -2803,10 +2805,10 @@ nvs_native_create(nvstream_t *nvs, nvs_native_t *native, char *buf,
 	}
 }
 
-/*ARGSUSED*/
 static void
 nvs_native_destroy(nvstream_t *nvs)
 {
+	(void) nvs;
 }
 
 static int