mei: bus: use correct lock ordering

The correct lock order is
  cl_bus_lock
    device_lock
      me_clients_rwsem

This order was violated in bus rescan and remove routines
when me_client_rwsem was locked before cl_bus_lock.

Chain exists of:
[    4.321653]   &dev->device_lock --> &dev->me_clients_rwsem -->
&dev->cl_bus_lock
[    4.321653]
[    4.321679]  Possible unsafe locking scenario:
[    4.321679]
[    4.321693]        CPU0                    CPU1
[    4.321701]        ----                    ----
[    4.321709]   lock(&dev->cl_bus_lock);
[    4.321720]
lock(&dev->me_clients_rwsem);
[    4.321733]                                lock(&dev->cl_bus_lock);
[    4.321745]   lock(&dev->device_lock);
[    4.321755]
[    4.321755]  *** DEADLOCK ***
[    4.321755]

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