kernel: Move to Linux 4.16.4-openpower1

These patches are upstream now so are dropped from our tree:

 powerpc/eeh: Fix race with driver un/bind
 powerpc/mm/radix: Fix checkstops caused by invalid tlbiel

Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/openpower/configs/barreleye_defconfig b/openpower/configs/barreleye_defconfig
index 4ddeb75..cb26a52 100644
--- a/openpower/configs/barreleye_defconfig
+++ b/openpower/configs/barreleye_defconfig
@@ -14,7 +14,7 @@
 BR2_ROOTFS_POST_BUILD_SCRIPT="../openpower/scripts/fixup-target-var ../openpower/scripts/firmware-whitelist"
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y
-BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.16.1"
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.16.4"
 BR2_LINUX_KERNEL_PATCH="$(BR2_EXTERNAL_OP_BUILD_PATH)/linux"
 BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
 BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="$(BR2_EXTERNAL_OP_BUILD_PATH)/configs/linux/skiroot_defconfig"