drm/msm/sde: avoid vbif and wb register dumps in secure mode

VBIF and WB register HLOS access is revoked during
secure-display session. Dumping those registers at
ping pong done timeout causes access violation.
Hence avoid vbif and wb register space dumping in secure mode.

Change-Id: I5d327178e9f6232257b3d2fbfef8ca7ef78db2e1
Signed-off-by: Lakshmi Narayana Kalavala <lkalaval@codeaurora.org>