Revert "iommu: fix build error when CONFIG_IOMMU_API is off"

virt inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I61SPO


CVE: NA

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

This reverts commit 3afa66c6.

Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
Reviewed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>