drm/i915: Introduce i915_has_asle()

We want to allow the desktop PNV to not have .is_mobile set. To
that end let's add a small helper to determine if the platform
has the ASLE interrupt (or equivalent). Supposdely both PNV
variants have it.

Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190318165633.28924-4-ville.syrjala@linux.intel.comReviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

drivers/gpu/drm/i915/i915_irq.c

@@ -748,13 +748,21 @@ void i915_disable_pipestat(struct drm_i915_private *dev_priv,
 	POSTING_READ(reg);
 }
 
+static bool i915_has_asle(struct drm_i915_private *dev_priv)
+{
+	if (!dev_priv->opregion.asle)
+		return false;
+
+	return IS_PINEVIEW(dev_priv) || IS_MOBILE(dev_priv);
+}
+
 /**
  * i915_enable_asle_pipestat - enable ASLE pipestat for OpRegion
  * @dev_priv: i915 device private
  */
 static void i915_enable_asle_pipestat(struct drm_i915_private *dev_priv)
 {
-	if (!dev_priv->opregion.asle || !IS_MOBILE(dev_priv))
+	if (!i915_has_asle(dev_priv))
 		return;
 
 	spin_lock_irq(&dev_priv->irq_lock);