staging: greybus: Fix warning to limit chars per line

Wrap comment to fix warning "prefer a maximum 75 chars per line"

Signed-off-by: Gaurav Dhingra <gauravdhingra.gxyd@gmail.com>
Acked-by: Vaibhav Agarwal <vaibhav.sr@gmail.com>
Reviewed-by: Mark Greer <mgreer@animalcreek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>