WD_HPRE:Optimize code based on coding specifications

driver inclusion
category: bugfix
bugzilla: NA
CVE: NA

Fix the sparse warining checked by tools:
1. Inner function use Key static.
2. Using macro replace Key const.

Feature or Bugfix:Bugfix

Signed-off-by: liulongfang <liulongfang@huawei.com>
Reviewed-by: xuzaibo <xuzaibo@huawei.com>
Reviewed-by: Zhou Wang <wangzhou1@hisilicon.com>
Reviewed-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>