stmmac: fix max coal timer parameter

This patch is to fix the max coalesce timer setting that can be provided
by ethtool.
The default value (STMMAC_COAL_TX_TIMER) was used in the set_coalesce helper
instead of the max one (STMMAC_MAX_COAL_TX_TICK, so defined but not used).
Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -696,7 +696,7 @@ static int stmmac_set_coalesce(struct net_device *dev,
 	    (ec->tx_max_coalesced_frames == 0))
 		return -EINVAL;
 
-	if ((ec->tx_coalesce_usecs > STMMAC_COAL_TX_TIMER) ||
+	if ((ec->tx_coalesce_usecs > STMMAC_MAX_COAL_TX_TICK) ||
 	    (ec->tx_max_coalesced_frames > STMMAC_TX_MAX_FRAMES))
 		return -EINVAL;