ARM: OMAP2+: Fix LCD panel backlight regression for LDP legacy booting

Looks like the LCD panel on LDP has been broken quite a while, and
recently got fixed by commit 0b2aa8b (gpio: twl4030: Fix regression
for twl gpio output). However, there's still an issue left where the panel
backlight does not come on if the LCD drivers are built into the
kernel.

Fix the issue by registering the DPI LCD panel only after the twl4030
GPIO has probed.

Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
[tony@atomide.com: updated per Tomi's comments]
Signed-off-by: Tony Lindgren <tony@atomide.com>

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

@@ -242,12 +242,18 @@ static void __init ldp_display_init(void)
 
 static int ldp_twl_gpio_setup(struct device *dev, unsigned gpio, unsigned ngpio)
 {
+	int res;
+
 	/* LCD enable GPIO */
 	ldp_lcd_pdata.enable_gpio = gpio + 7;
 
 	/* Backlight enable GPIO */
 	ldp_lcd_pdata.backlight_gpio = gpio + 15;
 
+	res = platform_device_register(&ldp_lcd_device);
+	if (res)
+		pr_err("Unable to register LCD: %d\n", res);
+
 	return 0;
 }
 
@@ -346,7 +352,6 @@ static struct omap2_hsmmc_info mmc[] __initdata = {
 
 static struct platform_device *ldp_devices[] __initdata = {
 	&ldp_gpio_keys_device,
-	&ldp_lcd_device,
 };
 
 #ifdef CONFIG_OMAP_MUX