* Add LZ4 decompressor
LZ4 gives a better compression ratio than the previously used CK compress. The bootloader can now decompress both LZ4 compressed files and CK compressed files.
* rpifwcrypto: Add GET_CRYPTO_PRIVATE_KEY mailbox API
For provisioning, add a new mailbox API which returns the private key
in DER format. The API will return an error if the key-status for
the specified key is LOCKED.
* config: Add support for board_attributes in conditional expressions
Add support for the board-attributes row in config.txt conditional
expressions. This can be used to change boot behavior for
Compute Module Lite / No-WiFi etc.
* board_info: Log the OTP board revision at startup
Log the board revision plus the raw OTP value at startup.
