ARM vf610: add compatibilty strings of supported Vybrid SoC's

The Vybrid SoC family (in the kernel known as vf610) is a familiy
of multiple similar SoC's. The VF5xx series comes without secondary
Cortex-M4 core, while the second number VFx1x indicates the presence
of a L2 cache controller.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

Documentation/devicetree/bindings/arm/fsl.txt

@@ -75,6 +75,18 @@ i.MX6q generic board
 Required root node properties:
     - compatible = "fsl,imx6q";
 
+Freescale Vybrid Platform Device Tree Bindings
+----------------------------------------------
+
+For the Vybrid SoC familiy all variants with DDR controller are supported,
+which is the VF5xx and VF6xx series. Out of historical reasons, in most
+places the kernel uses vf610 to refer to the whole familiy.
+
+Required root node compatible property (one of them):
+    - compatible = "fsl,vf500";
+    - compatible = "fsl,vf510";
+    - compatible = "fsl,vf600";
+    - compatible = "fsl,vf610";
 
 Freescale LS1021A Platform Device Tree Bindings
 ------------------------------------------------

arch/arm/mach-imx/mach-vf610.c

@@ -13,11 +13,14 @@
 #include <asm/hardware/cache-l2x0.h>
 
 static const char * const vf610_dt_compat[] __initconst = {
+	"fsl,vf500",
+	"fsl,vf510",
+	"fsl,vf600",
 	"fsl,vf610",
 	NULL,
 };
 
-DT_MACHINE_START(VYBRID_VF610, "Freescale Vybrid VF610 (Device Tree)")
+DT_MACHINE_START(VYBRID_VF610, "Freescale Vybrid VF5xx/VF6xx (Device Tree)")
 	.l2c_aux_val	= 0,
 	.l2c_aux_mask	= ~0,
 	.dt_compat	= vf610_dt_compat,