ppc-7.0 queue

* Exception model rework (Fabiano)
* Unused CPU models removal (Fabiano and Cédric)
* Fix for VOF installation (Alexey)
* Misc fixes

# gpg: Signature made Thu 10 Feb 2022 12:59:07 GMT
# gpg:                using RSA key A0F66548F04895EBFE6B0B6051A343C7CFFBECA1
# gpg: Good signature from "Cédric Le Goater <clg@kaod.org>" [undefined]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: A0F6 6548 F048 95EB FE6B  0B60 51A3 43C7 CFFB ECA1

* remotes/legoater/tags/pull-ppc-20220210: (42 commits)
  spapr/vof: Install rom and nvram binaries
  docs: rstfy confidential guest documentation
  target/ppc: Change VSX instructions behavior to fill with zeros
  target/ppc: books: Remove excp_model argument from ppc_excp_apply_ail
  target/ppc: Assert if MSR bits differ from msr_mask during exceptions
  target/ppc: powerpc_excp: Move common code to the caller function
  target/ppc: Remove powerpc_excp_legacy
  target/ppc: 7xx: Set SRRs directly in exception code
  target/ppc: 7xx: Software TLB cleanup
  target/ppc: 7xx: System Reset cleanup
  target/ppc: 7xx: System Call exception cleanup
  target/ppc: 7xx: Program exception cleanup
  target/ppc: 7xx: External interrupt cleanup
  target/ppc: 7xx: Machine Check exception cleanup
  target/ppc: Simplify powerpc_excp_7xx
  target/ppc: Introduce powerpc_excp_7xx
  target/ppc: Merge 7x5 and 7x0 exception model IDs
  target/ppc: 6xx: Set SRRs directly in exception code
  target/ppc: 6xx: Software TLB exceptions cleanup
  target/ppc: 6xx: System Reset interrupt cleanup
  ...

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