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.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_display.c

@@ -3154,11 +3154,7 @@ static bool transcoder_has_m2_n2(struct drm_i915_private *dev_priv,
 	if (IS_HASWELL(dev_priv))
 		return transcoder == TRANSCODER_EDP;
 
-	/*
-	 * Strictly speaking some registers are available before
-	 * gen7, but we only support DRRS on gen7+
-	 */
-	return DISPLAY_VER(dev_priv) == 7 || IS_CHERRYVIEW(dev_priv);
+	return IS_DISPLAY_VER(dev_priv, 5, 7) || IS_CHERRYVIEW(dev_priv);
 }
 
 void intel_cpu_transcoder_set_m1_n1(struct intel_crtc *crtc,