mwifiex: Remove unused 'adapter'variable

Commit 3935ccc14d2c introduced mwifiex_tm_cmd() which initializes
struct mwifiex_adapter* adapter, but doesn't use it.
Compiling with W=1 gives the following warning, fix it.
mwifiex/cfg80211.c: In function ‘mwifiex_tm_cmd’:
mwifiex/cfg80211.c:3973:26: warning: variable ‘adapter’ set but not used [-Wunused-but-set-variable]

Fixes: 3935ccc14d2c ("mwifiex: add cfg80211 testmode support")
Cc: Xinming Hu <huxm@marvell.com>
Cc: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kirtika Ruchandani <kirtika@google.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/marvell/mwifiex/cfg80211.c

@@ -3990,13 +3990,11 @@ static int mwifiex_tm_cmd(struct wiphy *wiphy, struct wireless_dev *wdev,
 	struct mwifiex_private *priv = mwifiex_netdev_get_priv(wdev->netdev);
 	struct mwifiex_ds_misc_cmd *hostcmd;
 	struct nlattr *tb[MWIFIEX_TM_ATTR_MAX + 1];
-	struct mwifiex_adapter *adapter;
 	struct sk_buff *skb;
 	int err;
 
 	if (!priv)
 		return -EINVAL;
-	adapter = priv->adapter;
 
 	err = nla_parse(tb, MWIFIEX_TM_ATTR_MAX, data, len,
 			mwifiex_tm_policy);