mei: remove check on pm_runtime_active in __mei_cl_disconnect

Remove bogus check on pm_runtime_active that prevented
disconnection from a client in case the device was resuming
from power gating but not yet active.

Fix regression introduced by
18901357
mei: disconnect on connection request timeout

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>