pds_core: no health-thread in VF path

The VFs don't run the health thread, so don't try to
stop or restart the non-existent timer or work item.

Fixes: d9407ff1

 ("pds_core: Prevent health thread from running during reset/remove")
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Link: https://lore.kernel.org/r/20240210002002.49483-1-shannon.nelson@amd.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>