imx: ventana: gw5904/gw5909: disable RS485

The GW5904/GW5909 have a SP33E multi-protocol serial transceiver which we
want to configure to RS232 by default (by de-asserting RS485_EN)

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
diff --git a/board/gateworks/gw_ventana/common.c b/board/gateworks/gw_ventana/common.c
index 8934f21..8786a12 100644
--- a/board/gateworks/gw_ventana/common.c
+++ b/board/gateworks/gw_ventana/common.c
@@ -1429,6 +1429,8 @@
 		break;
 	case GW5909:
 	case GW5904:
+		gpio_request(IMX_GPIO_NR(4, 23), "rs485_en");
+		gpio_direction_output(IMX_GPIO_NR(4, 23), 0);
 		gpio_request(IMX_GPIO_NR(5, 11), "skt1_wdis#");
 		gpio_direction_output(IMX_GPIO_NR(5, 11), 1);
 		gpio_request(IMX_GPIO_NR(5, 12), "skt1_rst#");