mei: bus: use zero vtag for bus clients.

The zero vtag is required for the read flow to work also for
devices on the mei client bus.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20200818115147.2567012-10-tomas.winkler@intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>