disp: msm: dp: add pixel base offset support in device tree

Parse pixel base offset from "qcom,pixel-base-off" node in device
tree to differentiate pixel base offset in different hardwares.

Change-Id: Ia8eac1a7c3dba3eaff6b88cd7f6a467f288cdf4b
Signed-off-by: Xiaowen Wu <wxiaowen@codeaurora.org>
Signed-off-by: Soutrik Mukhopadhyay <quic_mukhopad@quicinc.com>
Signed-off-by: Nilesh Laad <quic_nlaad@quicinc.com>