kernel: Move to Linux v4.16.7-openpower1

Some powerpc fixes that are brought in with this release:

 cpufreq: powernv: Fix hardlockup due to synchronous smp_call in timer interrupt
 rtc: opal: Fix OPAL RTC driver OPAL_BUSY loops
 powerpc/powernv/npu: Do a PID GPU TLB flush when invalidating a large address range
 powerpc/mce: Fix a bug where mce loops on memory UE.
 powerpc/mm: Flush cache on memory hot(un)plug

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
index 430b646..11e144e 100644
--- a/openpower/linux/0002-Release-OpenPower-kernel.patch
+++ b/openpower/linux/0002-Release-OpenPower-kernel.patch
@@ -1,6 +1,6 @@
 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
 From: Joel Stanley <joel@jms.id.au>
-Date: Tue, 1 May 2018 15:51:50 +0930
+Date: Thu, 3 May 2018 12:21:12 +0930
 Subject: [PATCH 2/2] Release OpenPower kernel
 
 Signed-off-by: Joel Stanley <joel@jms.id.au>
@@ -9,13 +9,13 @@
  1 file changed, 1 insertion(+), 1 deletion(-)
 
 diff --git a/Makefile b/Makefile
-index 41f07b2b7905..c2ccade3bf95 100644
+index 1c5d5d8c45e2..ea0dccd03e90 100644
 --- a/Makefile
 +++ b/Makefile
 @@ -2,7 +2,7 @@
  VERSION = 4
  PATCHLEVEL = 16
- SUBLEVEL = 6
+ SUBLEVEL = 7
 -EXTRAVERSION =
 +EXTRAVERSION = -openpower1
  NAME = Fearless Coyote