board_misoc: reuse riscv dir for comm & kernel

artiq/firmware/libboard_misoc/build.rs

@@ -1,19 +1,16 @@
 extern crate build_misoc;
 extern crate cc;
 
-use std::env;
 use std::path::Path;
 
 fn main() {
     build_misoc::cfg();
 
-    let triple = env::var("TARGET").unwrap();
-    let arch = triple.split("-").next().unwrap();
-    let vectors_path = Path::new(arch).join("vectors.S");
+    let vectors_path = "riscv32/vectors.S";
 
-    println!("cargo:rerun-if-changed={}", vectors_path.to_str().unwrap());
+    println!("cargo:rerun-if-changed={}", vectors_path);
     cc::Build::new()
         .flag("--target=riscv32-unknown-elf")
-        .file(vectors_path)
+        .file(Path::new(vectors_path))
         .compile("vectors");
 }

artiq/firmware/libboard_misoc/lib.rs

@@ -8,7 +8,7 @@ extern crate log;
 extern crate smoltcp;
 
 #[cfg(target_arch = "riscv32")]
-#[path = "riscv32ima/mod.rs"]
+#[path = "riscv32/mod.rs"]
 mod arch;
 
 #[cfg(target_arch = "riscv32")]