Intel: ntb: intel: fix static declaration

mainline inclusion
from mainline-v5.8-rc1
commit 893733c5
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I47H3V
CVE: NA

--------------------------------

commit: 893733c5 upstream.

Backport summary: Backport to kernel 4.19.57 for 4th Gen Intel NTB support

intel_ntb4_link_disable() missing static declaration.
Reported-by: Nkbuild test robot <lkp@intel.com>
Signed-off-by: NDave Jiang <dave.jiang@intel.com>
Signed-off-by: NJon Mason <jdmason@kudzu.us>
Signed-off-by: NZheng Wu <wu.zheng@intel.com>
Signed-off-by: NJackie Liu <liuyun01@kylinos.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NXiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/ntb/hw/intel/ntb_hw_gen4.c

@@ -446,7 +446,7 @@ static int intel_ntb4_link_enable(struct ntb_dev *ntb,
 	return 0;
 }
 
-int intel_ntb4_link_disable(struct ntb_dev *ntb)
+static int intel_ntb4_link_disable(struct ntb_dev *ntb)
 {
 	struct intel_ntb_dev *ndev;
 	u32 ntb_cntl;