tpm: Fix reference count to main device

The main device is currently not properly released due to one additional
reference to the 'devs' device which is only released in case of a TPM 2.
So, also get the additional reference only in case of a TPM2.

Fixes: fdc915f ("tpm: expose spaces via a device link /dev/tpmrm<n>")
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

Author: stefanberger

drivers/char/tpm/tpm-chip.c

@@ -191,9 +191,10 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
 	/* get extra reference on main device to hold on
 	 * behalf of devs.  This holds the chip structure
 	 * while cdevs is in use.  The corresponding put
-	 * is in the tpm_devs_release
+	 * is in the tpm_devs_release (TPM2 only)
 	 */
-	get_device(&chip->dev);
+	if (chip->flags & TPM_CHIP_FLAG_TPM2)
+		get_device(&chip->dev);
 
 	if (chip->dev_num == 0)
 		chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);