tpm: fix compat 'ppi' link handling in tpm_chip_register()

__compat_only_sysfs_link_entry_to_kobj() was unconditionally called for
TPM1 chips, which caused crash on Acer C720 laptop where DSM for the
ACPI object did not exist.

There are two reasons for unwanted behavior:

* The code did not check whether
  __compat_only_sysfs_link_entry_to_kobj() returned -ENOENT. This is
  OK. It just meanst that ppi is not available.
* The code did not clean up properly. Compat link should added only
  after all other init is done.

This patch sorts out these issues.

Fixes: 9b774d5c
Reported-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jeremiah Mahler <jmmahler@gmail.com>
Acked-by: Peter Huewe <PeterHuewe@gmx.de>