ARM: shmobile: r7s72100: document MSTP clock support

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Magnus Damm <damm+renesas@opensource.se>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

Documentation/devicetree/bindings/clock/renesas,cpg-mstp-clocks.txt

@@ -10,6 +10,7 @@ index in the group, from 0 to 31.
 Required Properties:
 
   - compatible: Must be one of the following
+    - "renesas,r7s72100-mstp-clocks" for R7S72100 (RZ) MSTP gate clocks
     - "renesas,r8a7790-mstp-clocks" for R8A7790 (R-Car H2) MSTP gate clocks
     - "renesas,r8a7791-mstp-clocks" for R8A7791 (R-Car M2) MSTP gate clocks
     - "renesas,cpg-mstp-clock" for generic MSTP gate clocks