mei: add vtag support bit in client properties

mei: add vtag support bit in client properties

Vtag support is on a client basis, meaning not every client
supports it. The vtag capability is communicated via the client properties
structure during client enumeration process.
Export the propertiy via sysfs.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20200818115147.2567012-4-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>