msm: mdss: support panel topology configurations using module params

Starting patch I36dbf8d9e325675bb3affa1794b2fc93ee6151b4,
msm: mdss: enable different panel configuration modes, dsi panels can
have multiple topology configurations. Currently chosen configuration
is selected only through device tree using qcom,config-select property.
Add support to override this configuration using existing module param.
This module param can be changed by boot-loader display driver if present
or directly by user through kernel command line.

New module param usage:
panel=<lk_cfg>:<pan_intf>:<pan_intf_cfg>:<panel_topology_cfg>
where
<lk_cfg> = "1" lk/gcdb config or "0" non-lk/non-gcdb config;
<pan_intf> = dsi:<ctrl_id> or hdmi or edp;
<pan_intf_cfg> = panel interface specific string matching dt node name;
<panel_topology_cfg> = Optional. If used, format is "config%d";

Ex: panel=0:dsi:1:qcom,mdss_dsi_nt35597_dsc_wqxga_video:config2:0:none
    panel=0:dsi:0:qcom,mdss_dsi_nt35597_wqxga_cmd:config1:1:
          qcom,mdss_dsi_nt35597_wqxga_cmd:config1:cfg:split_dsi

Change-Id: I583ee801737282d3a0eb189e1bf8d66dd7a9b480
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>
Signed-off-by: Shivaraj Shetty <shivaraj@codeaurora.org>