msm: mdss: do not send blank event to interface in TWM entry

Sending MDSS_EVENT_BLANK turns off the panel.
For TWM entry to be successful do not send blank event.

Change-Id: I432049a2a44833f425bc64d5844442a234652c25
Signed-off-by: Sachin Bhayare <sachin.bhayare@codeaurora.org>