Remove all of the repos which are being automatically mirrored. The
addition of .mbedignore allows these repos to be used directly.
Also pull up on nanostack-hal-mbed-cmsis-rtos.lib to bring in new
features required by the updated repos.
The atmel-rf-driver-mirror repo is pointing to a SHA in the
atmel-rf-driver repo. This prevents mbed-os from building.
This patch updates atmel-rf-driver.lib to point to the correct
SHA.