TPM: tpm_nsc: Fix a double free of pdev in cleanup_nsc

platform_device_unregister() will release all resources
and remove it from the subsystem, then drop reference count by
calling platform_device_put().

We should not call kfree(pdev) after platform_device_unregister(pdev).

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>