Currently, in suspend() and resume(), ishtp client drivers are using
driver_data to get "struct ishtp_cl_device" object which is set by
bus driver. It's wrong since the driver_data should not be owned bus.
driver_data should be owned by the corresponding ishtp client driver.
Due to this, some ishtp client driver like cros_ec_ishtp which uses
its driver_data to transfer its data to its child doesn't work correctly.

So this patch removes setting driver_data in bus drier and instead of
using driver_data to get "struct ishtp_cl_device", since "struct device"
is embedded in "struct ishtp_cl_device", we introduce a helper function
that returns "struct ishtp_cl_device" from "struct device".
Signed-off-by: Hyungwoo Yang <hyungwoo.yang@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>