Bump Skiboot to latest p10 version containing Big-Core patches

This pulls a new Skiboot with significant changes, maily focused on
Big-Core support. Summary of changes since 85b27f5:

Benjamin Herrenschmidt (7):
      xive: Set the fused core mode properly
      chip: Fix pir_to_thread_id for fused cores
      cpu: Keep track of the "ec_primary" in big core more
      direct-ctl: Use the EC primary for special wakeups
      slw: Limit fused cores P9 to STOP0/1/2
      cpu: Make cpu_get_core_index() return the fused core number
      imc: Use pir_to_core_id() rather than cpu_get_core_index()

Cédric Le Goater (2):
      xive/p10: configure XIVE for fused cores
      xive/p10: Enforce thread enablement

Oliver O'Halloran (1):
      fix the bonus cleanup_cpu_state()

Ryan Grimm (1):
      Add basic P9 fused core support

Ryan P Grimm (1):
      Merge pull request #26 from svaidyan/p10-fusedcore

Vaidyanathan Srinivasan (6):
      Add POWER9 Cumulus processor PVR type
      Add POWER9 Fleetwood platform support
      Fused core support for P10
      chip: fixes for fused cores on P10
      xive/p10: add automatic Context Save and Restore support
      Enable fused core mode support in OPAL

Signed-off-by: Klaus Heinrich Kiwi <klaus@linux.vnet.ibm.com>

----------------

 asm/head.S               | 27 +++++++++++++++++++++++----
 core/chip.c              | 47 +++++++++++++++++++++++++++++++++++++++--------
 core/cpu.c               | 58 +++++++++++++++++++++++++++++++++++++++++++++-------------
 core/cpufeatures.c       | 19 +++++++++++++++++++
 core/direct-controls.c   |  8 ++++----
 core/fast-reboot.c       | 12 ++++++++++--
 core/init.c              |  4 ----
 hdata/test/hdata_to_dt.c |  9 ++++++++-
 hw/imc.c                 |  8 ++++----
 hw/slw.c                 | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/xive.c                |  6 +++++-
 hw/xive2.c               | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 include/chip.h           | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 include/cpu.h            | 13 +++++++++++++
 include/opal-api.h       |  1 +
 include/processor.h      | 37 +++++++++++++++++++++++++++++--------
 include/xive-p9-regs.h   |  1 +
 include/xive2-regs.h     | 20 +++++++++++++++++++-
 include/xscom.h          |  3 +++
 platforms/ibm-fsp/zz.c   |  4 ++++
 20 files changed, 426 insertions(+), 52 deletions(-)
diff --git a/openpower/configs/rainier_defconfig b/openpower/configs/rainier_defconfig
index c42c77b..4ce2325 100644
--- a/openpower/configs/rainier_defconfig
+++ b/openpower/configs/rainier_defconfig
@@ -25,7 +25,7 @@
 BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
 BR2_PACKAGE_SKIBOOT=y
 BR2_SKIBOOT_CUSTOM_VERSION=y
-BR2_SKIBOOT_CUSTOM_VERSION_VALUE="85b27f552e25e52e5a6c8fa334b0a082347d46b4"
+BR2_SKIBOOT_CUSTOM_VERSION_VALUE="8bb456166aeac415700ab04b68469aa10a8a359c"
 BR2_SKIBOOT_CUSTOM_GIT=y
 BR2_SKIBOOT_CUSTOM_REPO_URL="git@github.ibm.com:p10/skiboot.git"
 BR2_PACKAGE_BUSYBOX_CONFIG_FRAGMENT_FILES="$(BR2_EXTERNAL_OP_BUILD_PATH)/configs/busybox.fragment"