[WireGuard] wg doesn't build on 4.7 kernels

[Bruno Wolff III]

make[1]: Entering directory '/usr/src/kernels/4.7.0-0.rc5.git1.2.fc25.x86_64'
  CC [M]  /home/bruno/WireGuard/src/device.o
/home/bruno/WireGuard/src/device.c: In function ‘xmit’:
/home/bruno/WireGuard/src/device.c:112:5: error: ‘struct net_device’ has no member named ‘trans_start’; did you mean ‘mem_start’?
  dev->trans_start = jiffies;
     ^~