kobject: kobject_uevent() returns manageable value

Since kobject_uevent() function does not return an integer value to
indicate if its operation was completed with success or not, it is worth
changing it in order to report a proper status (success or error) instead
of returning void.

[randy.dunlap@oracle.com: Fix inline kobject functions]
Cc: Mauricio Lin <mauriciolin@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@gmail.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>