drm/i915/icl: Fix MG_DP_MODE() register programming

drm/i915/icl: Fix MG_DP_MODE() register programming

Fix the order of lane, port parameters passed to the register macro.

Note that this was already partly fixed by commit
37fc7845df7b6 ("drm/i915: Call MG_DP_MODE() macro with the right parameters order")

While at it simplify things by using the macro directly instead of an
unnecessary redirection via an array.

v2:
- Add a note the commit message about simplifying things. (José)

Fixes: 58106b7d816e1 ("drm/i915: Make MG PHY macros semantically consistent")
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Aditya Swarup <aditya.swarup@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190419071026.32370-1-imre.deak@intel.com