hikey: Switch to kernel prebuilt 4.9

Test: Manual

Change-Id: I25574ee3fc76d4f00114cf42f884457af628e1cc
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
diff --git a/hikey.mk b/hikey.mk
index db48242..40e1f8b 100644
--- a/hikey.mk
+++ b/hikey.mk
@@ -1,5 +1,5 @@
 ifndef TARGET_KERNEL_USE
-TARGET_KERNEL_USE=4.4
+TARGET_KERNEL_USE=4.9
 endif
 TARGET_PREBUILT_KERNEL := device/linaro/hikey-kernel/Image-dtb-$(TARGET_KERNEL_USE)
 TARGET_PREBUILT_DTB := device/linaro/hikey-kernel/hi6220-hikey.dtb-$(TARGET_KERNEL_USE)