Some devices want to do special things when recovery wipes data (eg,
wipe data in their baseband processor as well). Add a hook in the
device-specific recovery library that gets called when data is wiped.
Also add an amend root for the "mbm" partition.
Take some device-specific details of the recovery UI (eg, what keys to
press to bring up the interface and perform actions, exact text of the
menu, etc.) and split them out into separate C functions. Arrange to
take implementations of those functions from the appropriate vendor
directory at build time. Provide a default implementation in case no
vendor-specific one is available.
