stmmac: remove two useless initialisations

This patch removes two useless initialisations in the
stmmac_rx and stmmac_tx functions.
In the former, the count variable was reset twice and in
the stmmac_tx we only need to increment the dirty pointer
w/o setting the entry variable.

v2: review the subject and comment that was not clear in my
first version.
Signed-off-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -677,7 +677,7 @@ static void stmmac_tx(struct stmmac_priv *priv)
 
 		priv->hw->desc->release_tx_desc(p);
 
-		entry = (++priv->dirty_tx) % txsize;
+		priv->dirty_tx++;
 	}
 	if (unlikely(netif_queue_stopped(priv->dev) &&
 		     stmmac_tx_avail(priv) > STMMAC_TX_THRESH(priv))) {
@@ -1307,7 +1307,6 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
 		display_ring(priv->dma_rx, rxsize);
 	}
 #endif
-	count = 0;
 	while (!priv->hw->desc->get_rx_owner(p)) {
 		int status;