Merge remote-tracking branch 'remotes/alistair/tags/pull-dtc-next-20200320-1' into staging

DTC patches for 5.0

# gpg: Signature made Fri 20 Mar 2020 21:56:31 GMT
# gpg:                using RSA key F6C4AC46D4934868D3B8CE8F21E10D29DF977054
# gpg: Good signature from "Alistair Francis <alistair@alistair23.me>" [full]
# Primary key fingerprint: F6C4 AC46 D493 4868 D3B8  CE8F 21E1 0D29 DF97 7054

* remotes/alistair/tags/pull-dtc-next-20200320-1:
  device_tree: Add info message when dumping dtb to file

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