ARM: socfpga: dts: document "altr,stratix10-rst-mgr" binding

"altr,stratix10-rst-mgr" is used for the Stratix10 reset manager.

Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
diff --git a/Documentation/devicetree/bindings/reset/socfpga-reset.txt b/Documentation/devicetree/bindings/reset/socfpga-reset.txt
index 98c9f56..09a9c54e 100644
--- a/Documentation/devicetree/bindings/reset/socfpga-reset.txt
+++ b/Documentation/devicetree/bindings/reset/socfpga-reset.txt
@@ -1,7 +1,8 @@
 Altera SOCFPGA Reset Manager
 
 Required properties:
-- compatible : "altr,rst-mgr"
+- compatible : "altr,rst-mgr" for (Cyclone5/Arria5/Arria10)
+	       "altr,stratix10-rst-mgr" for Stratix10 ARM64 SoC
 - reg : Should contain 1 register ranges(address and length)
 - altr,modrst-offset : Should contain the offset of the first modrst register.
 - #reset-cells: 1