ram: stm32mp1: add driver

Add driver and binding for stm32mp1 ddr controller and phy

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/drivers/ram/stm32mp1/Makefile b/drivers/ram/stm32mp1/Makefile
new file mode 100644
index 0000000..9f05cd4
--- /dev/null
+++ b/drivers/ram/stm32mp1/Makefile
@@ -0,0 +1,8 @@
+#
+# Copyright (C) 2018, STMicroelectronics - All Rights Reserved
+#
+# SPDX-License-Identifier:	GPL-2.0+	BSD-3-Clause
+#
+
+obj-y += stm32mp1_ram.o
+obj-y += stm32mp1_ddr.o