mei: wd and amthif use mei_cl_ api for dis/connection

Connect wd and amthif through regular mei_cl_connect API
as there is no reason to connect in asynchronous mode.
Also use mei_cl_is_connected in order to protect flows
instead of depending on wd_pending and amthif_timer

Now we can remove all the special handling in hbm layer

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>