Merge remote-tracking branch 'remotes/dg-gitlab/tags/ppc-for-6.0-20210331' into staging

Merge remote-tracking branch 'remotes/dg-gitlab/tags/ppc-for-6.0-20210331' into staging

ppc patch queue for 2021-03-31

Here's another set of patches for the ppc target and associated
machine types.  I'd hoped to send this closer to the hard freeze, but
got caught up for some time chasing what looked like a strange
regression, before finally concluding it was due to unrelated failures
on the CI.

This is just a handful of fairly straightforward fixes, plus one
performance improvement that's simple and beneficial enough that I'm
considering it a "performance bug fix".

# gpg: Signature made Wed 31 Mar 2021 07:22:17 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/dg-gitlab/tags/ppc-for-6.0-20210331:
  hw/net: fsl_etsec: Tx padding length should exclude CRC
  spapr: Fix typo in the patb_entry comment
  spapr: Assert DIMM unplug state in spapr_memory_unplug()
  target/ppc/kvm: Cache timebase frequency
  hw/ppc: e500: Add missing #address-cells and #size-cells in the eTSEC node

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