staging: vt6655: remove redundant assignment of pointer tx_key

Pointer tx_key is being assigned a value that is never read, it is
being re-assigned a new value later. The assignment is redundant
and can be removed.

Cleans up clan scan build warning:
drivers/staging/vt6655/rxtx.c:1311:3: warning: Value stored
to 'tx_key' is never read [deadcode.DeadStores]

Signed-off-by: Colin Ian King <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/vt6655/rxtx.c

···
 			cpu_to_le16(ieee80211_get_hdrlen_from_skb(skb) << 10);
 
 	if (info->control.hw_key) {
-		tx_key = info->control.hw_key;
-
 		switch (info->control.hw_key->cipher) {
 		case WLAN_CIPHER_SUITE_WEP40:
 		case WLAN_CIPHER_SUITE_WEP104: