usb: dwc3: Add dwc3 glue driver support for STi

This patch adds the ST glue logic to manage the DWC3 HC
on STiH407 SoC family. It configures the internal glue
logic and syscfg registers.

Part of this code been extracted from kernel.org driver
(drivers/usb/dwc3/dwc3-st.c)

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/include/asm/arch-stih410/sys_proto.h

@@ -0,0 +1,11 @@
+/*
+ * Copyright (c) 2017
+ * Patrice Chotard <patrice.chotard@st.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _ASM_ARCH_SYS_PROTO_H
+#define _ASM_ARCH_SYS_PROTO_H
+
+#endif /* _ASM_ARCH_SYS_PROTO_H */