samsung: usb: phy: Support for DWC3 PHY

New files, namely samsung_usb_phy.c and samsung-usb-phy-uboot.h have
been added to u-boot to provide proper PHY handling at Exynos5 SoCs.

This code is used thereafter in the board_usb_init() call.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Marek Vasut <marex@denx.de>

include/samsung-usb-phy-uboot.h

@@ -0,0 +1,16 @@
+/* include/samsung-usb-phy-uboot.h
+ *
+ * Copyright (c) 2015 Samsung Electronics
+ *
+ * USB3 (DWC3) PHY uboot init
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#ifndef __SAMSUNG_USB_PHY_UBOOT_H_
+#define __SAMSUNG_USB_PHY_UBOOT_H_
+
+#include <asm/arch/xhci-exynos.h>
+
+void exynos5_usb3_phy_init(struct exynos_usb3_phy *phy);
+#endif /* __SAMSUNG_USB_PHY_UBOOT_H_ */