Update riscv32.rs

embassy-executor/src/arch/riscv32.rs

@@ -8,7 +8,7 @@ mod thread {
     use core::marker::PhantomData;
 
     pub use embassy_macros::main_riscv as main;
-    use portable_atomic::{AtomicBool, Ordering};
+    use core::sync::atomic::{AtomicBool, Ordering};
 
     use crate::{raw, Spawner};