net: ethernet: slicoss: remove redundant initialization of idx

Variable idx is being initialized and later on over-written by
a new value in a do-loop without the initial value ever being
read. Hence the initializion is redundant and can be removed.
Cleans up clang warning:

drivers/net/ethernet/alacritech/slicoss.c:358:15: warning: Value
stored to 'idx' during its initialization is never read
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NLino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/alacritech/slicoss.c

@@ -355,10 +355,10 @@ static void slic_xmit_complete(struct slic_device *sdev)
 {
 	struct slic_tx_queue *txq = &sdev->txq;
 	struct net_device *dev = sdev->netdev;
-	unsigned int idx = txq->done_idx;
 	struct slic_tx_buffer *buff;
 	unsigned int frames = 0;
 	unsigned int bytes = 0;
+	unsigned int idx;
 
 	/* Limit processing to SLIC_MAX_TX_COMPLETIONS frames to avoid that new
 	 * completions during processing keeps the loop running endlessly.