ethtool: Add 10base-T1L link mode entry

commit 1afdc662f4e4fe5c73b0665fc49b7a920ce6eea5 from
https://github.com/nxp-auto-linux/linux

Add entry for the 10base-T1L full duplex mode.

Issue: ALB-10440

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 3254e0b9

)
Signed-off-by: Zhantao Tang <zhantao.tang@windriver.com>