mwifiex: make function mwifiex_ret_pkt_aggr_ctrl static

function mwifiex_ret_pkt_aggr_ctrl can be made static as it does not
need to be in global scope.

Cleans up sparse warning: "symbol 'mwifiex_ret_pkt_aggr_ctrl' was not
declared. Should it be static?"
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/marvell/mwifiex/sta_cmdresp.c

@@ -1154,7 +1154,7 @@ static int mwifiex_ret_chan_region_cfg(struct mwifiex_private *priv,
 	return 0;
 }
 
-int mwifiex_ret_pkt_aggr_ctrl(struct mwifiex_private *priv,
+static int mwifiex_ret_pkt_aggr_ctrl(struct mwifiex_private *priv,
 				     struct host_cmd_ds_command *resp)
 {
 	struct host_cmd_ds_pkt_aggr_ctrl *pkt_aggr_ctrl =