tpm: missing tpm_chip_put in tpm_get_random()

commit 3e14d83ef94a5806a865b85b513b4e891923c19b upstream.

Regression in 41ab999c. Call to tpm_chip_put is missing. This
will cause TPM device driver not to unload if tmp_get_random()
is called.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>