mei: abort waiting for notification on unsupported HW

On legacy HW, pre Skylake, the notifications are not supported,
return -EOPNOTSUPP in mei_cl_notify_get and prevent
waiting indefinitely.

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