The RATP implementation now allows executing generic commands with a
binary interface: binary requests are received and binary responses
are returned.

Each command can define its own RATP request contents (e.g. to specify
command-specific options) as well as its own RATP response contents
(if any data is to be returned).

Each command is associated with a pair of numeric unique request and
response IDs, and for easy reference these IDs are maintained in the
common ratp_bb header. Modules may override generic implemented
commands or include their own new ones (as long as the numeric IDs
introduced are unique).

Signed-off-by: Aleksander Morgado <aleksander@aleksander.es>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>