smdk5250: Remove 'board_usb_vbus_init()' function

Previously as a part of moving the VBUS gpio support to device tree
following patch removed this and added relevant support in driver:
4a271cb exynos: usb: Switch USB VBUS GPIOs to be device tree configured

Recent changes for common board file migration for exynos platform
added it again. So removing it now.

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Cc: Julius Werner <jwerner@chromium.org>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Marek Vasut <marex@denx.de>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>

board/samsung/smdk5250/smdk5250.c

@@ -26,22 +26,6 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#ifdef CONFIG_USB_EHCI_EXYNOS
-static int board_usb_vbus_init(void)
-{
-	struct exynos5_gpio_part1 *gpio1 = (struct exynos5_gpio_part1 *)
-						samsung_get_base_gpio_part1();
-
-	/* Enable VBUS power switch */
-	s5p_gpio_direction_output(&gpio1->x2, 6, 1);
-
-	/* VBUS turn ON time */
-	mdelay(3);
-
-	return 0;
-}
-#endif
-
 #ifdef CONFIG_SOUND_MAX98095
 static void  board_enable_audio_codec(void)
 {
@@ -56,9 +40,6 @@ static void  board_enable_audio_codec(void)
 
 int exynos_init(void)
 {
-#ifdef CONFIG_USB_EHCI_EXYNOS
-	board_usb_vbus_init();
-#endif
 #ifdef CONFIG_SOUND_MAX98095
 	board_enable_audio_codec();
 #endif