tpm: check for TPM_CHIP_FLAG_TPM2 before calling tpm2_shutdown()

Fixes: 20e0152393b41 ("tpm: fix crash in tpm_tis deinitialization")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reported-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Tested-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-By: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>