cortex-m: update to volatile-register 0.2.2, fixes #485

Author: adamgreig

cortex-m/Cargo.toml

@@ -18,7 +18,7 @@ links = "cortex-m"  # prevent multiple versions of this crate to be linked toget
 
 [dependencies]
 critical-section = "1.0.0"
-volatile-register = "0.2.0"
+volatile-register = "0.2.2"
 bitfield = "0.13.2"
 embedded-hal = "0.2.4"