drm/i915: Fix ICL MG PHY vswing handling

commit a2a5f56 upstream.

The MH PHY vswing table does have all the entries these days. Get
rid of the old hacks in the code which claim otherwise.

This hack was totally bogus anyway. The correct way to handle the
lack of those two entries would have been to declare our max
vswing and pre-emph to both be level 2.

Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Clinton Taylor <clinton.a.taylor@intel.com>
Fixes: 9f7ffa2 ("drm/i915/tc/icl: Update TC vswing tables")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201207203512.1718-1-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
(cherry picked from commit 5ec3464)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: vsyrjala

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

@@ -2605,12 +2605,11 @@ static void icl_mg_phy_ddi_vswing_sequence(struct intel_encoder *encoder,
 
 	ddi_translations = icl_get_mg_buf_trans(encoder, type, rate,
 						&n_entries);
-	/* The table does not have values for level 3 and level 9. */
-	if (level >= n_entries || level == 3 || level == 9) {
+	if (level >= n_entries) {
 		drm_dbg_kms(&dev_priv->drm,
 			    "DDI translation not found for level %d. Using %d instead.",
-			    level, n_entries - 2);
-		level = n_entries - 2;
+			    level, n_entries - 1);
+		level = n_entries - 1;
 	}
 
 	/* Set MG_TX_LINK_PARAMS cri_use_fs32 to 0. */