Merge remote-tracking branch 'remotes/rth/tags/pull-or1k-20200116' into staging

Fix FPSCR masking

# gpg: Signature made Fri 17 Jan 2020 00:51:41 GMT
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [full]
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth/tags/pull-or1k-20200116:
  target/openrisc: Fix FPCSR mask to allow setting DZF

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