serial: sc16is7xx: remove unused line structure member

serial: sc16is7xx: remove unused line structure member

commit 41a308cbedb2a68a6831f0f2e992e296c4b8aff0 upstream.

Now that the driver has been converted to use one regmap per port, the line
structure member is no longer used, so remove it.

Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
Cc:  <stable@vger.kernel.org>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231211171353.2901416-4-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>