Release 4.4.21-openpower1

v4.4.21 stable release, which includes a fix for the fix for the NVMe
issue that is important for OpenPower machines.

Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/openpower/configs/firestone_defconfig b/openpower/configs/firestone_defconfig
index e2b641b..0da4ab8 100644
--- a/openpower/configs/firestone_defconfig
+++ b/openpower/configs/firestone_defconfig
@@ -42,7 +42,7 @@
 BR2_ROOTFS_POST_BUILD_SCRIPT="../openpower/scripts/fixup-target-var"
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y
-BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.4.20"
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.4.21"
 BR2_KERNEL_HEADERS_4_4=y
 BR2_BINUTILS_VERSION_2_26_X=y
 BR2_LINUX_KERNEL_PATCH="$(BR2_EXTERNAL)/linux"