powerpc/cacheinfo: Remove double free

kfree() after kobject_put(). Who ever wrote this was on crack.

Fixes: 7e803979

 ("powerpc/cacheinfo: Fix kobject memleak")
Signed-off-by: Tobin C. Harding <tobin@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>