Revert "drm/msm/sde: remove register access from sde probe"

This reverts commit 6fe7f679 ("drm/msm/sde: remove
register access from sde probe") because sde clocks are
accessible for sdm845 target.

Change-Id: I024ea5ded090bc19d8ed73d8baa44281e0da11aa
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>