drm/i915: Fix transcoder_has_m2_n2()

M2/N2 values are present for all ilk-ivb,vlv,chv (and hsw edp).
Make the code reflect that.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220128103757.22461-13-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>