packet: remove deprecated syststamp timestamp

No device driver will ever return an skb_shared_info structure with
syststamp non-zero, so remove the branch that tests for this and
optionally marks the packet timestamp as TP_STATUS_TS_SYS_HARDWARE.

Do not remove the definition TP_STATUS_TS_SYS_HARDWARE, as processes
may refer to it.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/if_packet.h b/include/uapi/linux/if_packet.h
index bac27fa0..da2d668 100644
--- a/include/uapi/linux/if_packet.h
+++ b/include/uapi/linux/if_packet.h
@@ -108,7 +108,7 @@
 
 /* Rx and Tx ring - header status */
 #define TP_STATUS_TS_SOFTWARE		(1 << 29)
-#define TP_STATUS_TS_SYS_HARDWARE	(1 << 30)
+#define TP_STATUS_TS_SYS_HARDWARE	(1 << 30) /* deprecated, never set */
 #define TP_STATUS_TS_RAW_HARDWARE	(1 << 31)
 
 /* Rx ring - feature request bits */