qlcnic: remove redundant assignment to variable index

Variable index is being assigned a value that is never read, it is being
re-assigned later in a following for-loop. The assignment is redundant
and can be removed.

Cleans up clang scan build warning:
drivers/net/ethernet/qlogic/qlcnic/qlcnic_ethtool.c:1358:17: warning:
Although the value stored to 'index' is used in the enclosing expression,
the value is never actually read from 'index' [deadcode.DeadStores]
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20220318012035.89482-1-colin.i.king@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/qlogic/qlcnic/qlcnic_ethtool.c

@@ -1355,7 +1355,7 @@ static void qlcnic_get_ethtool_stats(struct net_device *dev,
 
 	memset(data, 0, stats->n_stats * sizeof(u64));
 
-	for (ring = 0, index = 0; ring < adapter->drv_tx_rings; ring++) {
+	for (ring = 0; ring < adapter->drv_tx_rings; ring++) {
 		if (adapter->is_up == QLCNIC_ADAPTER_UP_MAGIC) {
 			tx_ring = &adapter->tx_ring[ring];
 			data = qlcnic_fill_tx_queue_stats(data, tx_ring);