greybus: protocol: Create request structure from within gb_protocol_get_version()

The version request can only send the version of protocol for which it
is initiated and gb_protocol_get_version() has all the information to
create the request structure.

Replace the 'request' and 'request_size' arguments to
gb_protocol_get_version() with a bool to know if the version information
of the protocol should be sent or not.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>