drm/i915/display: Re-add check for low voltage sku for max dp source rate

drm/i915/display: Re-add check for low voltage sku for max dp source rate

This reverts commit eac178dbb6eb ("drm/i915/display: Remove check for
low voltage sku for max dp source rate"), which, on an i7-11850H iGPU
with a Thinkpad X1 Extreme Gen 4, attached to a LG LP160UQ1-SPB1
embedded panel, causes wild flickering glitching technicolor
pyrotechnics on resumption from suspend. The display shows strobing
colors in an utter disaster explosion of pantone, as though bombs were
dropped on the leprechauns at the base of the rainbow.

Rebooting the machine fixes the issue, presumably because the display is
initialized by firmware rather than by i915. Otherwise, the GPU appears
to work fine.

Bisection traced it back to this commit, which makes sense given the
issues.

Note: This re-opens, and puts back to the drawing board,
https://gitlab.freedesktop.org/drm/intel/-/issues/5272 which was fixed
by the regressing commit.

Fixes: eac178dbb6eb ("drm/i915/display: Remove check for low voltage sku for max dp source rate")
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6205
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Cc: Jani Saarinen <jani.saarinen@intel.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220613102241.9236-1-Jason@zx2c4.com