kernel: Move to Linux v5.4.22-openpower1

PowerPC releated changes (since 5.4.16, as the bump to 5.4.18 omitted
any information):

 powerpc: Do not consider weak unresolved symbol relocations as bad
 powerpc/mm: Don't log user reads to 0xffffffff
 powerpc/papr_scm: Fix leaking 'bus_desc.provider_name' in some paths
 powerpc/ptdump: Only enable PPC_CHECK_WX with STRICT_KERNEL_RWX
 powerpc/ptdump: Fix W+X verification call in mark_rodata_ro()
 Revert "powerpc/pseries/iommu: Don't use dma_iommu_ops on secure guests"
 powerpc/kuap: Fix set direction in allow/prevent_user_access()
 mm/mmu_gather: invalidate TLB correctly on batch allocation failure and flush
 powerpc/futex: Fix incorrect user access blocking
 of: Add OF_DMA_DEFAULT_COHERENT & select it on powerpc
 powerpc/xmon: don't access ASDR in VMs
 powerpc/ptdump: Fix W+X verification
 powerpc/mmu_gather: enable RCU_TABLE_FREE even for !SMP case

Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/openpower/configs/opal_defconfig b/openpower/configs/opal_defconfig
index 7cf4cac..3777157 100644
--- a/openpower/configs/opal_defconfig
+++ b/openpower/configs/opal_defconfig
@@ -13,7 +13,7 @@
 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="5.4.18"
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.4.22"
 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"