We shouldn't restrict ourselves to just downclock modes with
lower refresh rate than the preferred mode. Laptops these
days can offer higher refresh rate modes as well.

Remove the arbitrary limit and allow all modes that, apart
from the clock, match the preferred mode.

v2: s/add_edid_downclock_modes/add_edid_alt_fixed_modes/ (Jani)
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220331112822.11462-9-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>