Merge remote-tracking branch 'remotes/rth/tags/pull-hppa-20181016' into staging

Queued hppa patch

# gpg: Signature made Tue 16 Oct 2018 23:45:46 BST
# gpg:                using RSA key 64DF38E8AF7E215F
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>"
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth/tags/pull-hppa-20181016:
  target/hppa: Raise exception 26 on emulated hardware

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