usb: new board-specific USB init interface

This commit unifies board-specific USB initialization implementations
under one symbol (usb_board_init), declaration of which is available in
usb.h.

New API allows selective initialization of USB controllers whenever needed.

Signed-off-by: Mateusz Zalega <m.zalega@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Lukasz Majewski <l.majewski@samsung.com>
diff --git a/board/nvidia/common/board.c b/board/nvidia/common/board.c
index 126e56e..1972527 100644
--- a/board/nvidia/common/board.c
+++ b/board/nvidia/common/board.c
@@ -32,6 +32,7 @@
 #ifdef CONFIG_USB_EHCI_TEGRA
 #include <asm/arch-tegra/usb.h>
 #include <asm/arch/usb.h>
+#include <usb.h>
 #endif
 #ifdef CONFIG_TEGRA_MMC
 #include <asm/arch-tegra/tegra_mmc.h>
@@ -153,8 +154,9 @@
 
 #ifdef CONFIG_USB_EHCI_TEGRA
 	pin_mux_usb();
-	board_usb_init(gd->fdt_blob);
+	usb_process_devicetree(gd->fdt_blob);
 #endif
+
 #ifdef CONFIG_LCD
 	tegra_lcd_check_next_stage(gd->fdt_blob, 0);
 #endif