Merge remote-tracking branch 'remotes/legoater/tags/pull-aspeed-20200918' into staging

Aspeed patches :

* Couple of cleanups
* New machine properties to define the flash models

# gpg: Signature made Fri 18 Sep 2020 08:23:19 BST
# 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-aspeed-20200918:
  misc: aspeed_scu: Update AST2600 silicon id register
  hw/arm/aspeed: Add machine properties to define the flash models
  hw/arm/aspeed: Map the UART5 device unconditionally

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