x86: msi-laptop: fix memleak

1. fix two visible mistakes:
    * when load_scm_model_init faild, we should call platform_device_del(msipf_device)
    * msipf_attribute_group should be remove in err case

2. change some tags, give them real meaning.

Signed-off-by: Libo Chen <libo.chen@huawei.com>
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>