Add RS485 support to Freescale iMX6

To add RS485 support to the UART on a Freescale iMX6 (SABRELITE) with kernel 3.10.17 apply the following patch.
Remember to set the appropriate GPIO for RTS signal in the Device Tree.
ftp://ftp.koansoftware.com/public/linux/freescale/imx6/imx6-3.10.17-serial-imx-rs485.patch