Revert "hammerhead: update prebuilt kernel"

This reverts commit 8e581c94eee35d05de0ed4ef5d7b383e1d4fd107.

Change-Id: I44e00786c01de146ac31a94584390a37e87b2eca
diff --git a/zImage-dtb b/zImage-dtb
index 117bc4d..df25b2f 100644
--- a/zImage-dtb
+++ b/zImage-dtb
Binary files differ