ARM: STi: Add STiH418 SoC support

This patch adds support to STiH418 SoC.
Signed-off-by: NMaxime Coquelin <maxime.coquelin@st.com>

Documentation/arm/sti/stih418-overview.txt

+			STiH418 Overview
+			================
+
+Introduction
+------------
+
+    The STiH418 is the new generation of SoC for UHDp60 set-top boxes
+    and server/connected client application for satellite, cable, terrestrial
+    and IP-STB markets.
+
+    Features
+    - ARM Cortex-A9 1.5 GHz quad core CPU (28nm)
+    - SATA2, USB 3.0, PCIe, Gbit Ethernet
+    - HEVC L5.1 Main 10
+    - VP9
+
+  Document Author
+  ---------------
+
+  Maxime Coquelin <maxime.coquelin@st.com>, (c) 2015 ST Microelectronics

Documentation/devicetree/bindings/arm/sti.txt

@@ -13,3 +13,7 @@ Boards with the ST STiH407 SoC shall have the following properties:
 Required root node property:
 compatible = "st,stih407";
 
+Boards with the ST STiH418 SoC shall have the following properties:
+Required root node property:
+compatible = "st,stih418";
+

arch/arm/mach-sti/board-dt.c

@@ -18,6 +18,7 @@ static const char *stih41x_dt_match[] __initdata = {
 	"st,stih415",
 	"st,stih416",
 	"st,stih407",
+	"st,stih418",
 	NULL
 };