idpf: prevent deinit uninitialized virtchnl core

In idpf_remove we need to tear down the virtchnl core with
idpf_vc_core_deinit so we can free up resources and leave things in a
good state. However, in the case where we failed to establish VC
communications we may not have ever actually successfully initialized
the virtchnl core.

This fixes it by setting a bit once we successfully init the virtchnl
core.  Then, in deinit, we'll check for it before going on further,
otherwise we just return. Also clear the bit at the end of deinit so we
know it's gone now.

Tested-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Alan Brady <alan.brady@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>