greybus: remove status from all responses

This is a pervasive change, but not really a big one.  However:

        ==============  Pay attention to this ==============
	If you're doing any testing with "gbsim" you need to
	update that program in sync with this change, because
	it changes the protocol used between them.
        ==============  Pay attention to this ==============

The status of a request is now recorded in the header of a response
message.  The previous patch put that header status byte in place,
and this one removes the status byte from all the response
messages.

And finally, since we're modifying all these files anyway...
Use gb_operation_status_map() to come up with a return code
to use, given an operation response.  Right now most errors
simply result in -EIO getting returned.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>