imx: ventana: add fdt fixup to enable UHS-I support on selected boards

UHS-I support is available on Ventana boards with micro-SD sockets depending
on the board revision. For backwards compatibility to not break users
who have old bootloaders and newer kernels the device-tree on boards with
microSD disables UHS-I support by default by defining the no-1-8-v property
in the esdhc controller node. For models/revisions that support switchable
1.8V/3.3V I/O which is detectable by the presence of a pull-down on the
SD3_VSELECT pin we remove that property to enable support in the kernel.

Additionally we add SD3_VSELECT to the pinmux for clarity (even though U-Boot
does not currently support UHS-I modes requiring 1.8V I/O).

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
diff --git a/board/gateworks/gw_ventana/common.h b/board/gateworks/gw_ventana/common.h
index 58ad5ff..d037767 100644
--- a/board/gateworks/gw_ventana/common.h
+++ b/board/gateworks/gw_ventana/common.h
@@ -17,6 +17,7 @@
 #define GP_SD3_CD	IMX_GPIO_NR(7, 0)
 #define GP_RS232_EN	IMX_GPIO_NR(2, 11)
 #define GP_MSATA_SEL	IMX_GPIO_NR(2, 8)
+#define GP_SD3_VSELECT	IMX_GPIO_NR(6, 14)
 
 #define UART_PAD_CTRL  (PAD_CTL_PKE | PAD_CTL_PUE |		\
 	PAD_CTL_PUS_100K_UP | PAD_CTL_SPEED_MED |		\
@@ -77,6 +78,7 @@
 	int usb_sel;
 	int wdis;
 	int msata_en;
+	bool usd_vsel;
 };
 
 extern struct ventana gpio_cfg[GW_UNKNOWN];