Documentation: add fsl-heap and imx-ion-pool docs

Signed-off-by: Antoine Bouyer <antoine.bouyer@nxp.com>
(cherry picked from commit eebe0cbb951dcf287b58ec0002d3e817be43d810)
diff --git a/Documentation/devicetree/bindings/staging/ion/fsl-heap.txt b/Documentation/devicetree/bindings/staging/ion/fsl-heap.txt
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+++ b/Documentation/devicetree/bindings/staging/ion/fsl-heap.txt
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+Freescale ION unmapped heap for i.MX
+
+Unmapped heap are used for security purpose, providing secure data
+path buffers for video decode and display.
+
+Required properties
+- compatible:
+  -  "fsl,display-heap" for display ion heap
+  -  "fsl,vpu-heap" for vpu decoder ion heap
+
+Required properties for Ion heaps
+- memory-region: one reserved mem region pointer.
+
+Example:
+  ion-display-region {
+    compatible = "fsl,display-heap", "linux,ion-heap-unmapped";
+    memory-region = <&display_region>;
+  };
+
diff --git a/Documentation/devicetree/bindings/staging/ion/imx-ion-pool.txt b/Documentation/devicetree/bindings/staging/ion/imx-ion-pool.txt
new file mode 100644
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+++ b/Documentation/devicetree/bindings/staging/ion/imx-ion-pool.txt
@@ -0,0 +1,17 @@
+Freescale reserved memory regions
+
+iMX reserved memory pool, being merged into cma region
+
+Required properties
+- compatible: "imx-ion-pool"
+
+Required properties:
+ - reg: (standard definition) static memory range
+
+
+Example:
+  vpu_region: imx_ion@2 {
+    compatible = "imx-ion-pool";
+    reg = <0x0 0xe4000000 0 0x02000000>;
+  };
+