hwsim: make testmode_cmd static

sparse correctly complains about this, no reason
for it not to be static.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mac80211_hwsim.c

@@ -729,7 +729,8 @@ static const struct nla_policy hwsim_testmode_policy[HWSIM_TM_ATTR_MAX + 1] = {
 
 static int hwsim_fops_ps_write(void *dat, u64 val);
 
-int mac80211_hwsim_testmode_cmd(struct ieee80211_hw *hw, void *data, int len)
+static int mac80211_hwsim_testmode_cmd(struct ieee80211_hw *hw,
+				       void *data, int len)
 {
 	struct mac80211_hwsim_data *hwsim = hw->priv;
 	struct nlattr *tb[HWSIM_TM_ATTR_MAX + 1];