tpm xen: Remove bogus tpm_chip_unregister

tpm_chip_unregister can only be called after tpm_chip_register.
devm manages the allocation so no unwind is needed here.

Cc: stable@vger.kernel.org
Fixes: afb5abc2 ("tpm: two-phase chip management functions")
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

drivers/char/tpm/xen-tpmfront.c

@@ -307,7 +307,6 @@ static int tpmfront_probe(struct xenbus_device *dev,
 	rv = setup_ring(dev, priv);
 	if (rv) {
 		chip = dev_get_drvdata(&dev->dev);
-		tpm_chip_unregister(chip);
 		ring_free(priv);
 		return rv;
 	}