uio: fix incorrect memory leak cleanup

Commit 75f0aef6 ("uio: fix memory leak") has fixed up some
memory leaks during the failure paths of the addition of uio
attributes, but still is not correct entirely. A kobject_uevent()
failure still needs a kobject_put() and the kobject container
structure allocation failure before the kobject_init() doesn't
need a kobject_put(). Fix this properly.

Fixes: 75f0aef6 ("uio: fix memory leak")
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>