dt-bindings: remoteproc: stm32_rproc: update for firmware synchronization

Add new properties description used to attach to a pre-loaded
firmware according to the commit 9276536f
("remoteproc: stm32: Parse syscon that will manage M4 synchronisation")
which updates the driver part.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Link: https://lore.kernel.org/r/20201014125441.2457-3-arnaud.pouliquen@st.comSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml

@@ -96,6 +96,19 @@ properties:
         3rd cell: register bitmask for the deep sleep bit
     maxItems: 1
 
+  st,syscfg-m4-state:
+    $ref: "/schemas/types.yaml#/definitions/phandle-array"
+    description: |
+      Reference to the tamp register which exposes the Cortex-M4 state.
+    maxItems: 1
+
+  st,syscfg-rsc-tbl:
+    $ref: "/schemas/types.yaml#/definitions/phandle-array"
+    description: |
+      Reference to the tamp register which references the Cortex-M4
+      resource table address.
+    maxItems: 1
+
   st,auto-boot:
     $ref: /schemas/types.yaml#/definitions/flag
     description:
@@ -122,6 +135,8 @@ examples:
       resets = <&rcc MCU_R>;
       st,syscfg-holdboot = <&rcc 0x10C 0x1>;
       st,syscfg-tz = <&rcc 0x000 0x1>;
+      st,syscfg-rsc-tbl = <&tamp 0x144 0xFFFFFFFF>;
+      st,syscfg-m4-state = <&tamp 0x148 0xFFFFFFFF>;
     };
 
 ...