drm/i915: Enable SAGV support for Gen12

BugLink: https://bugs.launchpad.net/bugs/1891451

Flip the switch and enable SAGV support
for Gen12 also.

Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200514074853.9508-4-stanislav.lisovskiy@intel.com
(cherry picked from commit 8ca6d02)
Signed-off-by: You-Sheng Yang <vicamo.yang@canonical.com>
Signed-off-by: Timo Aaltonen <timo.aaltonen@canonical.com>

drivers/gpu/drm/i915/intel_pm.c

@@ -3624,10 +3624,6 @@ 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;
 }