slimbus: core: use slim_device_update_status() to update status

use slim_device_update_status() instead of directly calling
the device_status() callback. Move slim_device_update_status() before
probe to avoid forward declaration too.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>