This helper function is called by the ai (*do_cmd) to setup and
start the async command based on the "mode" of operation. This
"mode" is determined by the cmd convert_src and start_src.
Move this "mode" determination and combine the functions.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>