Fix master compilation (#3977)

polkadot/xcm/pallet-xcm-benchmarks/src/mock.rs

@@ -21,7 +21,7 @@ use xcm_executor::traits::FilterAssetLocation;
 // An xcm sender/receiver akin to > /dev/null
 pub struct DevNull;
 impl xcm::opaque::latest::SendXcm for DevNull {
-	fn send_xcm(_: MultiLocation, _: Xcm<()>) -> SendResult {
+	fn send_xcm(_: impl Into<MultiLocation>, _: Xcm<()>) -> SendResult {
 		Ok(())
 	}
 }