omap3: beaglexm: fix DVI reset GPIO

GPIO reset line for Beagle XM is different from vanilla beagle
so we populate it as part of gpio update routine.

This in part fixes the issue of display not functioning on beagle XM
platform.

[nm@ti.com: split up, added descriptive changelogs]
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Koen Kooi <koen@beagleboard.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/board-omap3beagle.c

@@ -199,7 +199,7 @@ static struct omap_dss_device beagle_dvi_device = {
 	.name = "dvi",
 	.driver_name = "generic_panel",
 	.phy.dpi.data_lines = 24,
-	.reset_gpio = 170,
+	.reset_gpio = -EINVAL,
 	.platform_enable = beagle_enable_dvi,
 	.platform_disable = beagle_disable_dvi,
 };
@@ -307,6 +307,12 @@ static int beagle_twl_gpio_setup(struct device *dev,
 	else
 		gpio_direction_output(gpio + TWL4030_GPIO_MAX, 0);
 
+	/* DVI reset GPIO is different between beagle revisions */
+	if (omap3_beagle_get_rev() == OMAP3BEAGLE_BOARD_XM)
+		beagle_dvi_device.reset_gpio = 129;
+	else
+		beagle_dvi_device.reset_gpio = 170;
+
 	/* TWL4030_GPIO_MAX + 1 == ledB, PMU_STAT (out, active low LED) */
 	gpio_leds[2].gpio = gpio + TWL4030_GPIO_MAX + 1;