Contracts build risc-v fixtures (#2554)

Follow up from #2347 this time to verify that fixtures build to RISC-V

---------

Co-authored-by: alvicsam <alvicsam@gmail.com>
Co-authored-by: Alexander Samusev <41779041+alvicsam@users.noreply.github.com>
Co-authored-by: Alexander Theißen <alex.theissen@me.com>

substrate/frame/contracts/fixtures/contracts/call.rs

@@ -23,9 +23,11 @@ extern crate common;
 use uapi::{CallFlags, HostFn, HostFnImpl as api};
 
 #[no_mangle]
+#[polkavm_derive::polkavm_export]
 pub extern "C" fn deploy() {}
 
 #[no_mangle]
+#[polkavm_derive::polkavm_export]
 pub extern "C" fn call() {
 	let mut buffer = [0u8; 40];
 	let callee_input = 0..4;

substrate/frame/contracts/fixtures/contracts/common/Cargo.toml

@@ -6,6 +6,3 @@ authors.workspace = true
 edition.workspace = true
 license.workspace = true
 description = "Common utilities for pallet-contracts-fixtures."
-
-[lints]
-workspace = true

substrate/frame/contracts/fixtures/contracts/dummy.rs

@@ -20,7 +20,9 @@
 extern crate common;
 
 #[no_mangle]
+#[polkavm_derive::polkavm_export]
 pub extern "C" fn deploy() {}
 
 #[no_mangle]
+#[polkavm_derive::polkavm_export]
 pub extern "C" fn call() {}