ARM: dts: msm: enable HDMI & DSI displays on 8996 auto CDP platform

MSM8996 Auto CDP platform uses DSI-HDMI bridge chip. Add device
nodes to enable both native HDMI and one DSI-HDMI port for this
platform.

CRs-Fixed: 2043334
Change-Id: I30f43dd9e6ce1646a49c63522223d045e532ee24
Signed-off-by: Yujun Zhang <yujunzhang@codeaurora.org>