ixgbe: add a kernel documentation comment for ixgbe_ptp_get_ts_config

This function was missing a documentation comment. Add one now.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c

@@ -851,6 +851,15 @@ void ixgbe_ptp_rx_rgtstamp(struct ixgbe_q_vector *q_vector,
 	ixgbe_ptp_convert_to_hwtstamp(adapter, skb_hwtstamps(skb), regval);
 }
 
+/**
+ * ixgbe_ptp_get_ts_config - get current hardware timestamping configuration
+ * @adapter: pointer to adapter structure
+ * @ifr: ioctl data
+ *
+ * This function returns the current timestamping settings. Rather than
+ * attempt to deconstruct registers to fill in the values, simply keep a copy
+ * of the old settings around, and return a copy when requested.
+ */
 int ixgbe_ptp_get_ts_config(struct ixgbe_adapter *adapter, struct ifreq *ifr)
 {
 	struct hwtstamp_config *config = &adapter->tstamp_config;