kernel: Move to Linux v4.19.26-openpower1

PowerPC fixes (v4.19.14 through to v4.19.26):

 powerpc/radix: Fix kernel crash with mremap()
 powerpc/fadump: Do not allow hot-remove memory from fadump reserved area.
 powerpc/powernv/ioda: Allocate indirect TCE levels of cached userspace addresses on demand
 powerpc/perf: Fix thresholding counter data for unknown type
 powerpc/uaccess: fix warning/error with access_ok()
 powerpc/xmon: Fix invocation inside lock region
 powerpc/boot: Set target when cross-compiling for clang
 powerpc: Disable -Wbuiltin-requires-header when setjmp is used
 powerpc: avoid -mno-sched-epilog on GCC 4.9 and newer
 powerpc: consolidate -mno-sched-epilog into FTRACE flags
 powerpc: remove old GCC version checks
 powerpc/mm: Fallback to RAM if the altmap is unusable
 powerpc/mm: Fix linux page tables build with some configs

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 cd0a91b..695b62d 100644
--- a/openpower/linux/0002-Release-OpenPower-kernel.patch
+++ b/openpower/linux/0002-Release-OpenPower-kernel.patch
@@ -9,13 +9,13 @@
  1 file changed, 1 insertion(+), 1 deletion(-)
 
 diff --git a/Makefile b/Makefile
-index 892ff14cbc9d..eb33670b9cf9 100644
+index b71076cecba9..0fc730790bfa 100644
 --- a/Makefile
 +++ b/Makefile
 @@ -2,7 +2,7 @@
  VERSION = 4
  PATCHLEVEL = 19
- SUBLEVEL = 13
+ SUBLEVEL = 26
 -EXTRAVERSION =
 +EXTRAVERSION = -openpower1
  NAME = "People's Front"