Fix benchmarks compilation for 1.11 (#341)

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relay/kusama/src/lib.rs

@@ -1559,6 +1559,8 @@ impl pallet_nis::Config for Runtime {
 	type MaxIntakeWeight = MaxIntakeWeight;
 	type ThawThrottle = ThawThrottle;
 	type RuntimeHoldReason = RuntimeHoldReason;
+	#[cfg(feature = "runtime-benchmarks")]
+	type BenchmarkSetup = ();
 }
 
 parameter_types! {