shamu: update prebuilt kernel

bf4d16f net: wireless: bcmdhd: fix debug ring memory corruption

Linux version 3.10.40-gbf4d16f (android-build@wpiv14.hot.corp.google.com)
(gcc version 4.8 (GCC) )
 #1 SMP PREEMPT Tue Jun 21 17:56:24 UTC 2016 (master)

Bug: 28721405
Change-Id: Ib4da109c3ef6ee0894853220ca424ca98a3621d4
Source-Branch: android-msm-shamu-3.10
Signed-off-by: Ecco Park <eccopark@google.com>