drm/msm/dpu: remove dpu_mdss:hwversion

Unused and the extra rpm get/put interferes with handover from
bootloader (ie. happens before we have a chance to check if
things are already enabled).

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>