Kobject: remove kobject_register()

The function is no longer used by anyone in the kernel, and it prevents
the proper sending of the kobject uevent after the needed files are set
up by the caller.  kobject_init_and_add() can be used in its place.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>