habanalabs: check TPC vector pipe is empty

The driver waits for the TPC vector pipe to be empty before checking if the
TPC kernel has finished executing, but the code doesn't validate that the
pipe was indeed empty, it just wait for it without checking the return
value.

Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Tomer Tayar <ttayar@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>