Fixed some compilation issues for the blinky demo

Author: andresovela

examples/blinky-button-demo/Cargo.toml

@@ -8,6 +8,7 @@ edition = "2018"
 
 [dependencies]
 cortex-m = "0.6.2"
+cortex-m-rt = "0.6.12"
 rtt-target = {version = "0.2.0", features = ["cortex-m"] }
 nrf52832-hal = { features = ["rt"], path = "../../nrf52832-hal" }
 

examples/blinky-button-demo/src/main.rs

@@ -1,11 +1,11 @@
 #![no_main]
 #![no_std]
 
-use core::sync::atomic::{AtomicUsize, Ordering};
 use embedded_hal::digital::v2::InputPin;
 use embedded_hal::digital::v2::OutputPin;
 use nrf52832_hal as hal;
 use nrf52832_hal::gpio::Level;
+use rtt_target::{rprintln, rtt_init_print};
 
 #[panic_handler] // panicking behavior
 fn panic(_: &core::panic::PanicInfo) -> ! {