Revert "serial: sc16is7xx: Clear RS485 bits in the shutdown"

This reverts commit 927728a3.

Once the uart_port->rs485->flag is set to SER_RS485_ENABLED, the port
should always work in RS485 mode. If users want the port to leave
RS485 mode, they need to call ioctl() to clear SER_RS485_ENABLED.

So here we shouldn't clear the RS485 bits in the shutdown().

Fixes: 927728a3 ("serial: sc16is7xx: Clear RS485 bits in the shutdown")
Signed-off-by: Hui Wang <hui.wang@canonical.com>
Link: https://lore.kernel.org/r/20220418094339.678144-1-hui.wang@canonical.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/sc16is7xx.c

@@ -1238,12 +1238,10 @@ static void sc16is7xx_shutdown(struct uart_port *port)
 
 	/* Disable all interrupts */
 	sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
-	/* Disable TX/RX, clear auto RS485 and RTS invert */
+	/* Disable TX/RX */
 	sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
 			      SC16IS7XX_EFCR_RXDISABLE_BIT |
-			      SC16IS7XX_EFCR_TXDISABLE_BIT |
-			      SC16IS7XX_EFCR_AUTO_RS485_BIT |
-			      SC16IS7XX_EFCR_RTS_INVERT_BIT,
+			      SC16IS7XX_EFCR_TXDISABLE_BIT,
 			      SC16IS7XX_EFCR_RXDISABLE_BIT |
 			      SC16IS7XX_EFCR_TXDISABLE_BIT);