ram: stm32mp1: add driver

Add driver and binding for stm32mp1 ddr controller and phy

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>

arch/arm/mach-stm32mp/include/mach/ddr.h

@@ -0,0 +1,12 @@
+/*
+ * Copyright (C) 2018, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier:	GPL-2.0+	BSD-3-Clause
+ */
+
+#ifndef __MACH_STM32MP_DDR_H_
+#define __MACH_STM32MP_DDR_H_
+
+int board_ddr_power_init(void);
+
+#endif