Merge remote-tracking branch 'remotes/dgibson/tags/ppc-for-5.1-20200720' into staging

ppc patch queue 20200720

Here are some assorted fixes for qemu-5.1:
 * SLOF update with improved TPM handling, and fix for possible stack
   overflows on many-vcpu machines
 * Fix for NUMA distances on NVLink2 attached GPU memory nodes
 * Fixes to fail more gracefully on attempting to plug unsupported PCI bridge types
 * Don't allow pnv-psi device to be user created

# gpg: Signature made Mon 20 Jul 2020 06:29:21 BST
# gpg:                using RSA key 75F46586AE61A66CC44E87DC6C38CACA20D9B392
# gpg: Good signature from "David Gibson <david@gibson.dropbear.id.au>" [full]
# gpg:                 aka "David Gibson (Red Hat) <dgibson@redhat.com>" [full]
# gpg:                 aka "David Gibson (ozlabs.org) <dgibson@ozlabs.org>" [full]
# gpg:                 aka "David Gibson (kernel.org) <dwg@kernel.org>" [unknown]
# Primary key fingerprint: 75F4 6586 AE61 A66C C44E  87DC 6C38 CACA 20D9 B392

* remotes/dgibson/tags/ppc-for-5.1-20200720:
  pseries: Update SLOF firmware image
  spapr: Add a new level of NUMA for GPUs
  spapr_pci: Robustify support of PCI bridges
  ppc/pnv: Make PSI device types not user creatable

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>