The new interp4 definitions add support for more remote methods with
sequences of multi-byte data, sequences of sequences, plain integers
interleaved with sequences, and constant-size data other than 32-bit
integers. The new definitions are complex and can't fit in a simple
macro. Switch the remotectl interface to interp4, split it into a header
and source file, and update the users.
Signed-off-by: Richard Acayan <mailingradian@gmail.com>
