dt: bindings: tegra20-emc: Document interrupt property

EMC has a dedicated interrupt that is used to notify about completion of
HW operations. Document the interrupt property.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-emc.txt

@@ -10,6 +10,7 @@ Properties:
   and chosen using the ramcode board selector. If omitted, only one
   set of tables can be present and said tables will be used
   irrespective of ram-code configuration.
+- interrupts : Should contain EMC General interrupt.
 
 Child device nodes describe the memory settings for different configurations and clock rates.
 
@@ -20,6 +21,7 @@ Example:
 		#size-cells = < 0 >;
 		compatible = "nvidia,tegra20-emc";
 		reg = <0x7000f4000 0x200>;
+		interrupts = <0 78 0x04>;
 	}