mwifiex: Remove unused 'sta_ptr' variable

Commit 429d90d2 introduced mwifiex_cmd_tdls_oper() which initializes
struct mwifiex_sta_node* sta_ptr, but does not use it. Compiling with W=1 gives
the following warning, fix it.
mwifiex/sta_cmd.c: In function ‘mwifiex_cmd_tdls_oper’:
mwifiex/sta_cmd.c:1732:27: warning: variable ‘sta_ptr’ set but not used [-Wunused-but-set-variable]

Fixes: 429d90d2 ("mwifiex: add cfg80211 tdls_oper handler support")
Cc: Avinash Patil <patila@marvell.com>
Signed-off-by: Kirtika Ruchandani <kirtika@google.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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

@@ -1746,7 +1746,6 @@ mwifiex_cmd_tdls_oper(struct mwifiex_private *priv,
 {
 	struct host_cmd_ds_tdls_oper *tdls_oper = &cmd->params.tdls_oper;
 	struct mwifiex_ds_tdls_oper *oper = data_buf;
-	struct mwifiex_sta_node *sta_ptr;
 	struct host_cmd_tlv_rates *tlv_rates;
 	struct mwifiex_ie_types_htcap *ht_capab;
 	struct mwifiex_ie_types_qos_info *wmm_qos_info;
@@ -1764,7 +1763,6 @@ mwifiex_cmd_tdls_oper(struct mwifiex_private *priv,
 
 	tdls_oper->reason = 0;
 	memcpy(tdls_oper->peer_mac, oper->peer_mac, ETH_ALEN);
-	sta_ptr = mwifiex_get_sta_entry(priv, oper->peer_mac);
 
 	pos = (u8 *)tdls_oper + sizeof(struct host_cmd_ds_tdls_oper);