tpm_tis_core: Turn on the TPM before probing IRQ's

The interrupt probing sequence in tpm_tis_core cannot obviously run with
the TPM power gated. Power on the TPM with tpm_chip_start() before
probing IRQ's. Turn it off once the probing is complete.

Cc: linux-stable@vger.kernel.org
Fixes: a3fbfae8

 ("tpm: take TPM chip power gating out of tpm_transmit()")
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>