3rdparty/libgfxinit: Update submodule pointer

This includes a huge set of refactorings to support Core Display Clock
(CDClk) frequency switching based on the current mode requirements.

The CDClk is configurable since Haswell and runtime switching is suppor-
ted since Broadwell. Always using the lowest possible frequency setting
should allow some power-savings. While, on the upper end, we can support
higher resolution panels now, without having to change the static confi-
guration.

There have also been some smaller changes and fixes, including:
  o Parsing of eDP 1.4+ DPCD link rates, enables panels that don't
    advertise a maximum link rate but only individual ones.
  o DP support for Ibex Peak.
  o Corrected limit for HDMI on G45 to 165MHz.
  o Reworked GMBUS reset handling and timeouts, should help with
    stalled GMBUS controllers when unimplemented ports were probed
    by accident.

Tested on various boards from GM45 to KBL-R.

Change-Id: I0a90bd4afe2091699a46a5a1323af9723ff43018
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35898
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

3rdparty/libgfxinit

@@ -1 +1 @@
-Subproject commit a815704c84b4823f5b723404a37efed9d6c85d66
+Subproject commit fe7985f2a0692bc773d470a92ec54d22d3c12e4b