Fix format of pref64 option.

The lifetime is not shifted left three bits, It's divided by 8
(so shifted right 3 bits), but it's also a 13-bit integer that
occupies the beginning of a 16-bit field. So it's effectively
the same as a 16-bit integer with the least significant 3 bits
replaced by the plc.

Bug: 153694684
Test: ROOTFS=net_test.rootfs.amd64.buster.20200129 ../net_test/run_net_test.sh
Change-Id: Ibf7f5372f31439794cc196f0fd27b60b9fd176bd
1 file changed
tree: 501be22564f034fdc0fb2a8e30b767fe59e66e36
  1. devicetree/
  2. net/
  3. Android.bp