kobject: drop newline from msg string

There is currently a missing terminating newline in non-switch case
match when msg == NULL

Signed-off-by: Bo YU <tsu.yubo@gmail.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>