ARM: realview: add EB syscon variants to bindings

There are two distinct RealView EB system controller that we need
to detect and handle because their register layout differ
slightly.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/arm/arm-boards

@@ -123,7 +123,9 @@ Required nodes:
 
 - syscon: some subnode of the RealView SoC node must be a
   system controller node pointing to the control registers,
-  with the compatible string set to one of these tuples:
+  with the compatible string set to one of these:
+   "arm,realview-eb11mp-revb-syscon", "arm,realview-eb-syscon", "syscon"
+   "arm,realview-eb11mp-revc-syscon", "arm,realview-eb-syscon", "syscon"
    "arm,realview-eb-syscon", "syscon"
    "arm,realview-pb1176-syscon", "syscon"
    "arm,realview-pb11mp-syscon", "syscon"