hikey: Bump default kernel to 4.19

Been kind of sitting on this for awhile, but there's
not much reason not to move to 4.19 for HiKey

Change-Id: I70311affa222e84f544569445692001a8b160623
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/hikey-common.mk b/hikey-common.mk
index 77ea15b..a2cb460 100644
--- a/hikey-common.mk
+++ b/hikey-common.mk
@@ -1,5 +1,5 @@
 ifndef TARGET_KERNEL_USE
-TARGET_KERNEL_USE=4.14
+TARGET_KERNEL_USE=4.19
 endif
 
 HIKEY_USE_DRM_HWCOMPOSER := false