drm/msm: Revert "drm/msm: Stop using iommu_present()"

drm/msm: Revert "drm/msm: Stop using iommu_present()"

This reverts commit e2a88eabb02410267519b838fb9b79f5206769be. The commit
in question makes msm_use_mmu() check whether the DRM 'component master'
device is translated by the IOMMU. At this moment it is the 'mdss'
device.
However on platforms using the MDP5 driver (e.g. MSM8916/APQ8016,
MSM8996/APQ8096) it's the mdp5 device, which has the iommus property
(and thus is "translated by the IOMMU"). This results in these devices
being broken with the following lines in the dmesg.

[drm] Initialized msm 1.9.0 20130625 for 1a00000.mdss on minor 0
msm 1a00000.mdss: [drm:adreno_request_fw] loaded qcom/a300_pm4.fw from new location
msm 1a00000.mdss: [drm:adreno_request_fw] loaded qcom/a300_pfp.fw from new location
msm 1a00000.mdss: [drm:get_pages] *ERROR* could not get pages: -28
msm 1a00000.mdss: could not allocate stolen bo
msm 1a00000.mdss: [drm:get_pages] *ERROR* could not get pages: -28
msm 1a00000.mdss: [drm:msm_alloc_stolen_fb] *ERROR* failed to allocate buffer object
msm 1a00000.mdss: [drm:msm_fbdev_create] *ERROR* failed to allocate fb

Getting the mdp5 device pointer from this function is not that easy at
this moment. Thus this patch is reverted till the MDSS rework [1] lands.
It will make the mdp5/dpu1 device component master and the check will be
legit.

[1] https://patchwork.freedesktop.org/series/98525/

Fixes: e2a88eabb024 ("drm/msm: Stop using iommu_present()")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220419130422.1033699-1-dmitry.baryshkov@linaro.org
Signed-off-by: Rob Clark <robdclark@chromium.org>