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/linux/0002-Release-OpenPower-kernel.patch b/openpower/linux/0002-Release-OpenPower-kernel.patch
new file mode 100644
index 0000000..b0e3d0c
--- /dev/null
+++ b/openpower/linux/0002-Release-OpenPower-kernel.patch
@@ -0,0 +1,23 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Joel Stanley <joel@jms.id.au>
+Date: Mon, 9 Apr 2018 12:03:25 +0930
+Subject: [PATCH 2/2] Release OpenPower kernel
+
+Signed-off-by: Joel Stanley <joel@jms.id.au>
+---
+ Makefile | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/Makefile b/Makefile
+index d51175192ac1..9aacc376200a 100644
+--- a/Makefile
++++ b/Makefile
+@@ -2,7 +2,7 @@
+ VERSION = 4
+ PATCHLEVEL = 16
+ SUBLEVEL = 4
+-EXTRAVERSION =
++EXTRAVERSION = -openpower1
+ NAME = Fearless Coyote
+ 
+ # *DOCUMENTATION*