msm: Bringup 2 instances of ADV7533 for 8996

Bringup 2 instances of ADV7533 for 8996. Change all register writes
from constant to pdata variables. Move the DBA init from
mdss_dsi.c to mdss_dsi_panel.c.

Change-Id: Ib0fc9f7c2348efa04a44bc021cb50973e90d7f22
Signed-off-by: Siddharth Zaveri <szaveri@codeaurora.org>