drm/i915/tgl: disable SAGV temporarily

SAGV is not currently working for Tiger Lake. We better disable it until
the implementation is stabilized and we can enable it.

HSDES: 1409542895 2208191909
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190904213419.27547-6-jose.souza@intel.comSigned-off-by: José Roberto de Souza <jose.souza@intel.com>

drivers/gpu/drm/i915/intel_pm.c

@@ -3654,6 +3654,10 @@ static bool skl_needs_memory_bw_wa(struct drm_i915_private *dev_priv)
 static bool
 intel_has_sagv(struct drm_i915_private *dev_priv)
 {
+	/* HACK! */
+	if (IS_GEN(dev_priv, 12))
+		return false;
+
 	return (IS_GEN9_BC(dev_priv) || INTEL_GEN(dev_priv) >= 10) &&
 		dev_priv->sagv_status != I915_SAGV_NOT_CONTROLLED;
 }