net: ethernet: stmmac: platform: fix outdated function header

Fix the OF-helper function header to reflect that the function no longer
has a platform-data parameter.

Fixes: b0003ead75f3 ("stmmac: make stmmac_probe_config_dt return the
platform data struct")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -200,7 +200,6 @@ static int stmmac_dt_phy(struct plat_stmmacenet_data *plat,
 /**
  * stmmac_probe_config_dt - parse device-tree driver parameters
  * @pdev: platform_device structure
- * @plat: driver data platform structure
  * @mac: MAC address to use
  * Description:
  * this function is to read the driver parameters from device-tree and