drm/nouveau/tegra: Stop using iommu_present()

stable inclusion
from stable-v5.10.117
commit 819796024cceb8c63cad8e0632412f5d69bd402a
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L66B

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=819796024cceb8c63cad8e0632412f5d69bd402a



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

commit 87fd2b09 upstream.

Even if some IOMMU has registered itself on the platform "bus", that
doesn't necessarily mean it provides translation for the device we
care about. Replace iommu_present() with a more appropriate check.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
[added cc for stable]
Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: stable@vger.kernel.org # v5.0+
Link: https://patchwork.freedesktop.org/patch/msgid/70d40ea441da3663c2824d54102b471e9a621f8a.1649168494.git.robin.murphy@arm.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>