mlxsw: spectrum: Fix misuse of hard_header_len

BugLink: https://bugs.launchpad.net/bugs/1878232

commit feb7d387 upstream.

In order to specify that the mlxsw spectrum driver needs additional
headroom for packets, there have been use of the hard_header_len field of
the netdevice struct.

This commit changes that to use needed_headroom instead, as this is the
correct way to do that.

Fixes: 56ade8fe ("mlxsw: spectrum: Add initial support for Spectrum ASIC")
Signed-off-by: Yotam Gigi <yotamg@mellanox.com>
Acked-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -1261,7 +1261,7 @@ static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port)
 	/* Each packet needs to have a Tx header (metadata) on top all other
 	 * headers.
 	 */
-	dev->hard_header_len += MLXSW_TXHDR_LEN;
+	dev->needed_headroom = MLXSW_TXHDR_LEN;
 
 	err = mlxsw_sp_port_module_check(mlxsw_sp_port, &usable);
 	if (err) {