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

This reverts commit d5929835.

With the Parade PS8461E MUX workaround (WaEdpLinkRateDataReload)
implemented we can get finally rid of the is_low_voltage_sku()
check that incorrectly prevents many machines from using the
8.1Gpbs link rate.

Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5272
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6323
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6205


Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220902070319.15395-2-ville.syrjala@linux.intel.com


Tested-by: Aaron Ma <aaron.ma@canonical.com>
Tested-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>