serial: ar933x: Deassert Transmit Enable on ->rs485_config()

serial: ar933x: Deassert Transmit Enable on ->rs485_config()

commit 3a939433ddc1bab98be028903aaa286e5e7461d7 upstream.

The ar933x_uart driver neglects to deassert Transmit Enable when
->rs485_config() is invoked.  Fix it.

Fixes: 9be1064fe524 ("serial: ar933x_uart: add RS485 support")
Cc: stable@vger.kernel.org # v5.7+
Cc: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Ilpo JÀrvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>