iwlagn: remove unused old_assoc parameter

old_assoc not used, remove it
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

drivers/net/wireless/iwlwifi/iwl-agn-rxon.c

@@ -289,7 +289,6 @@ int iwlagn_commit_rxon(struct iwl_priv *priv, struct iwl_rxon_context *ctx)
 	/* cast away the const for active_rxon in this function */
 	struct iwl_rxon_cmd *active = (void *)&ctx->active;
 	bool new_assoc = !!(ctx->staging.filter_flags & RXON_FILTER_ASSOC_MSK);
-	bool old_assoc = !!(ctx->active.filter_flags & RXON_FILTER_ASSOC_MSK);
 	int ret;
 
 	lockdep_assert_held(&priv->mutex);