Adding changelog entry

Author: ryan-summers

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - [breaking-change] Add a 2 ms delay after changing SDIO card power setting.
 - [breaking-change] Changed sdio::{read, write}_block buf argument to &[u8; 512].
 - Voltage regulator overdrive is enabled where supported and required for selected HCLK.
+- I2C driver updated to detect and clear all error condition flags.
 
 ### Added