fix tests

Author: TDHolmes

Diff for: testsuite/src/main.rs

@@ -28,11 +28,12 @@ mod tests {
 
     #[test]
     #[cfg(not(feature = "semihosting"))] // QEMU does not model the cycle counter
+    #[cfg_attr(armv6m, allow(unused_variables))]
     fn cycle_count(p: &mut cortex_m::Peripherals) {
+        use cortex_m::peripheral::DWT;
+
         #[cfg(not(armv6m))]
         {
-            use cortex_m::peripheral::DWT;
-
             assert!(DWT::has_cycle_counter());
 
             p.DCB.enable_trace();