ixgbe: fix uninitialized event.type in ixgbe_ptp_check_pps_event

This patch fixes a bug in ixgbe_ptp_check_pps_event where the type was
uninitialized and could cause unknown event outcomes.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
index 842ba15..01d99af 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
@@ -387,6 +387,15 @@
 	struct ixgbe_hw *hw = &adapter->hw;
 	struct ptp_clock_event event;
 
+	event.type = PTP_CLOCK_PPS;
+
+	/* this check is necessary in case the interrupt was enabled via some
+	 * alternative means (ex. debug_fs). Better to check here than
+	 * everywhere that calls this function.
+	 */
+	if (!adapter->ptp_clock)
+		return;
+
 	switch (hw->mac.type) {
 	case ixgbe_mac_X540:
 		ptp_clock_event(adapter->ptp_clock, &event);