Build wasm for mvp cpu (paritytech#13758)

Author: athei

utils/wasm-builder/src/wasm_project.rs

@@ -632,7 +632,7 @@ fn build_project(
 	let mut build_cmd = cargo_cmd.command();
 
 	let rustflags = format!(
-		"-C link-arg=--export-table {} {}",
+		"-C target-cpu=mvp -C link-arg=--export-table {} {}",
 		default_rustflags,
 		env::var(crate::WASM_BUILD_RUSTFLAGS_ENV).unwrap_or_default(),
 	);