disp: msm: dsi: Add support for parsing mdp_intf base address from dt

Currently, mdp_intf_line_count and mdp_intf_tear_line_count register
addresses are defined in dsi_ctrl_hw for debug feature. But mdp_intf
base address is target specific and independent of dsi controller
version. This change adds support for parsing the mdp intf base
address from dt, thereby remapping using base + offset addressing.

Change-Id: Ibb72dfe84a786a5c8b95f6a400e8333f6b46814a
Signed-off-by: Lipsa Rout <lrout@codeaurora.org>