igb: cleanup some of the code related to hw timestamping

The code for the hw timestamping is a bit bulky and making some of the
functions difficult to read.  In order to clean things up a bit I am moving
the timestamping operations into seperate functions.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/igb/igb.h b/drivers/net/igb/igb.h
index bef8cdc1..1a0ae57 100644
--- a/drivers/net/igb/igb.h
+++ b/drivers/net/igb/igb.h
@@ -323,6 +323,7 @@
 #define IGB_FLAG_QUAD_PORT_A       (1 << 2)
 #define IGB_FLAG_QUEUE_PAIRS       (1 << 3)
 
+#define IGB_82576_TSYNC_SHIFT 19
 enum e1000_state_t {
 	__IGB_TESTING,
 	__IGB_RESETTING,