drm/i915/gtt: Full ppgtt everywhere, no excuses

We believe we have all the kinks worked out, even for the early
Valleyview devices, for whom we currently disable all ppgtt.

References: 62942ed7279d ("drm/i915/vlv: disable PPGTT on early revs v3")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180717095751.1034-2-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -173,12 +173,6 @@ int intel_sanitize_enable_ppgtt(struct drm_i915_private *dev_priv,
 		return 0;
 	}
 
-	/* Early VLV doesn't have this */
-	if (IS_VALLEYVIEW(dev_priv) && dev_priv->drm.pdev->revision < 0xb) {
-		DRM_DEBUG_DRIVER("disabling PPGTT on pre-B3 step VLV\n");
-		return 0;
-	}
-
 	if (has_full_48bit_ppgtt)
 		return 3;