mei: start disconnect request timer consistently

commit 22b987a3 upstream.

Link must be reset in case the fw doesn't
respond to client disconnect request.
We did charge the timer only in irq path
from mei_cl_irq_close and not in mei_cl_disconnect

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>