greybus: control: Print bundle-id in print messages

The new power management specific operations added to the control
protocol do not print the bundle-id in the error messages and it is not
possible to identify which bundle-id the operation failed for.

Fix that and do minor rewriting of the print messages to make them more
readable.

Tested on EVT 2.0 with gpbridge-test module.

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