Replace futures::future::poll_fn -> core::future::poll_fn.

embassy-stm32/src/usart/buffered.rs

@@ -1,11 +1,10 @@
-use core::future::Future;
+use core::future::{poll_fn, Future};
 use core::task::Poll;
 
 use atomic_polyfill::{compiler_fence, Ordering};
 use embassy_cortex_m::peripheral::{PeripheralMutex, PeripheralState, StateStorage};
 use embassy_hal_common::ring_buffer::RingBuffer;
 use embassy_sync::waitqueue::WakerRegistration;
-use futures::future::poll_fn;
 
 use super::*;