msm: mdss: disable dsi timing db once fps is updated

In the current implementation, once dynamic fps update
kicks in, MDSS driver enables DSI timing db property.
But from chipsets like sdm660, DSI_CMD_OFFSET and
DSI_CMD_LENGTH register has become double buffered and
since timing db property was enabled as part of dynamic
fps update, DSI commands transfer for backlight update,
panel health check or panel off might fail if there is
no control flush. So disable DSI timing db property once
dynamic fps update sequence is complete.

Change-Id: I5158a36c9eea8f257ec81bab2f260e072fc22f29
Signed-off-by: Sandeep Panda <spanda@codeaurora.org>