doubletalk: probe failure causes OOPS

The code bothers to probe for the device, but on failing to find it proceeds
to try and release a NULL resource, thereby ruining it's prior good
behaviour

Resolves-Bug: https://bugzilla.kernel.org/show_bug.cgi?id=88581


Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>