Switch back to upstream cortex-m now changes merged in.
Switch back to upstream cortex-m now changes merged in.

thejpster/bare-metal-arm-rust,thejpster/kinetis-frdm,thejpster/launchpad-rs,thejpster/bare-metal-arm-rust,thejpster/kinetis-frdm,thejpster/launchpad-rs