[kernel]: update sonic linux kernel (#1645)

lguohan · web-flow · commit 8d2a30a75baa · 2018-04-26T13:53:39.000-07:00
b511c96 2018-04-17 | Add kexec reboot string (#46) (HEAD, origin/master, origin/HEAD) [Joe LeVeque] Signed-off-by: Guohan Lu <gulv@microsoft.com>
diff --git a/src/sonic-linux-kernel b/src/sonic-linux-kernel
@@ -1 +1 @@
-Subproject commit ed04b36903885ec065274174aa775e47695db2cb
+Subproject commit b511c96bcea09ae2b2adb3c3df7c4c41f14b6929
