drm/i915: remove redundant fbc warnings

The fbc enabled/active sanity checks are already done in
__intel_fbc_disable so no need to do them again.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1467710914-15146-1-git-send-email-matthew.auld@intel.com

drivers/gpu/drm/i915/intel_fbc.c

@@ -1165,11 +1165,8 @@ void intel_fbc_disable(struct intel_crtc *crtc)
 		return;
 
 	mutex_lock(&fbc->lock);
-	if (fbc->crtc == crtc) {
-		WARN_ON(!fbc->enabled);
-		WARN_ON(fbc->active);
+	if (fbc->crtc == crtc)
 		__intel_fbc_disable(dev_priv);
-	}
 	mutex_unlock(&fbc->lock);
 
 	cancel_work_sync(&fbc->work.work);