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/ti/omap5_uevm/evm.c b/board/ti/omap5_uevm/evm.c
index 5fc3473..228df29 100644
--- a/board/ti/omap5_uevm/evm.c
+++ b/board/ti/omap5_uevm/evm.c
@@ -184,7 +184,7 @@
 		eth_setenv_enetaddr("usbethaddr", device_mac);
 	}
 
-	ret = omap_ehci_hcd_init(&usbhs_bdata, hccr, hcor);
+	ret = omap_ehci_hcd_init(index, &usbhs_bdata, hccr, hcor);
 	if (ret < 0) {
 		puts("Failed to initialize ehci\n");
 		return ret;