target: msm8996: add split display support for hdmi

Enable side by side split display feature on HDMI for
static splash case, animation splash case and rearview
camera case. When enabling this feature by user, HDMI
will ouput a super frame, side by side split with two
independent splash buffers on panel.

Change-Id: Idc27a7f111d0ae5646b67faed6de487e922ec0ee
Signed-off-by: Guchun Chen <guchunc@codeaurora.org>