kernel: Move to Linux v5.3.18-openpower1

PowerPC releated changes:

 powerpc: Fix vDSO clock_getres()
 powerpc: Avoid clang warnings around setjmp and longjmp
 powerpc/xive: Skip ioremap() of ESB pages for LSI interrupts
 powerpc: Allow flush_icache_range to work across ranges >4GB
 powerpc/xive: Prevent page fault issues in the machine crash handler
 powerpc: Allow 64bit VDSO __kernel_sync_dicache to work across ranges >4GB
 powerpc/perf: Disable trace_imc pmu

The XHCI patch had to be modified to apply cleanly, as the xhci_shutdown
code was refactored.

Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/openpower/configs/opal_defconfig b/openpower/configs/opal_defconfig
index 7a780b3..26ce092 100644
--- a/openpower/configs/opal_defconfig
+++ b/openpower/configs/opal_defconfig
@@ -12,7 +12,7 @@
 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="5.3.16"
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.3.18"
 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"