The clean up procedure now uses platform device "release" callback to
handle memory clean up. For this purpose "release" function callback was
added to struct tpm_vendor_specific, so hw device driver provider can get
called when it is safe to remove all allocated resources.
This is supposed to fix a bug in device removal, where device while in
receive function (waiting on timeout) was prone to segfault, if the
tpm_chip struct was unallocated before the timeout expired (in
tpm_remove_hardware).