drm/i915: remove too-frequent FBC debug message

If we run igt/kms_frontbuffer_tracking, this message will appear
thousands of times, eating a significant part of our dmesg buffer.
It's part of the expected FBC behavior, so let's just silence it.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1446664257-32012-10-git-send-email-paulo.r.zanoni@intel.comSigned-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

drivers/gpu/drm/i915/intel_fbc.c

@@ -376,8 +376,6 @@ static void intel_fbc_cancel_work(struct drm_i915_private *dev_priv)
 	if (dev_priv->fbc.fbc_work == NULL)
 		return;
 
-	DRM_DEBUG_KMS("cancelling pending FBC enable\n");
-
 	/* Synchronisation is provided by struct_mutex and checking of
 	 * dev_priv->fbc.fbc_work, so we can perform the cancellation
 	 * entirely asynchronously.