drm/msm: Depopulate platform on probe failure

add_display_components() calls of_platform_populate, and we depopluate
on pdev remove, but not when probe fails. So if we get a probe deferral
in one of the components, we won't depopulate the platform. This causes
the core to keep references to devices which should be destroyed, which
causes issues when those same devices try to re-initialize on the next
probe attempt.

I think this is the reason we had issues with the gmu's device-managed
resources on deferral (worked around in commit 94e3a17f33a5).

Reviewed-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190617201301.133275-3-sean@poorly.run