net: stmmac: allow a tc-taprio base-time of zero

Commit fe28c53e ("net: stmmac: fix taprio configuration when
base_time is in the past") allowed some base time values in the past,
but apparently not all, the base-time value of 0 (Jan 1st 1970) is still
explicitly denied by the driver.

Remove the bogus check.

Fixes: b60189e0 ("net: stmmac: Integrate EST with TAPRIO scheduler API")
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: NKurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

@@ -786,8 +786,6 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
 		goto disable;
 	if (qopt->num_entries >= dep)
 		return -EINVAL;
-	if (!qopt->base_time)
-		return -ERANGE;
 	if (!qopt->cycle_time)
 		return -ERANGE;