drm/i915: Move the common RPS warnings to intel_set_rps()

Instead of having each back-end provide identical guards, just have a
singular set in intel_set_rps() to verify that the caller is obeying the
rules.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Radoslaw Szwichtenberg <radoslaw.szwichtenberg@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170220094713.22874-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_pm.c

@@ -4914,10 +4914,6 @@ static u32 gen6_rps_pm_mask(struct drm_i915_private *dev_priv, u8 val)
  * update the GEN6_RP_INTERRUPT_LIMITS register accordingly. */
 static int gen6_set_rps(struct drm_i915_private *dev_priv, u8 val)
 {
-	WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
-	WARN_ON(val > dev_priv->rps.max_freq);
-	WARN_ON(val < dev_priv->rps.min_freq);
-
 	/* min/max delay may still have been modified so be sure to
 	 * write the limits value.
 	 */
@@ -4955,10 +4951,6 @@ static int valleyview_set_rps(struct drm_i915_private *dev_priv, u8 val)
 {
 	int err;
 
-	WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
-	WARN_ON(val > dev_priv->rps.max_freq);
-	WARN_ON(val < dev_priv->rps.min_freq);
-
 	if (WARN_ONCE(IS_CHERRYVIEW(dev_priv) && (val & 1),
 		      "Odd GPU freq value\n"))
 		val &= ~1;
@@ -5109,6 +5101,10 @@ int intel_set_rps(struct drm_i915_private *dev_priv, u8 val)
 {
 	int err;
 
+	lockdep_assert_held(&dev_priv->rps.hw_lock);
+	GEM_BUG_ON(val > dev_priv->rps.max_freq);
+	GEM_BUG_ON(val < dev_priv->rps.min_freq);
+
 	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
 		err = valleyview_set_rps(dev_priv, val);
 	else