Staging: ste_rmi4: use after input_unregister_device()

The original code called input_free_device(rmi4_data->input_dev) after
input_unregister_device(rmi4_data->input_dev) and that's a double free.
This is described in the comments to input_unregister_device().

The normal way to handle this is to make input_register_device() the
last function in the probe which can fail.  That way you can avoid the
call to input_unregister_device() entirely.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>