msm_fb: display: Send pixel data while sending on/off commands

To avoid LCD off sequence violeation for some LCD vendors,
we need to keep sending video data during off/sleep commands.
This fixes issues seen while going to a suspend.

Crs-Fixed: 445707
Change-Id: I0ba2704502e8959d0f82deea60481cd5b1f0be20
Signed-off-by: Siddhartha Agrawal <agrawals@codeaurora.org>