Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20190211' into staging

Fix dynamic tlb resize
Fix x86 host vector saturation
Diagnose missing tcg labels

# gpg: Signature made Mon 11 Feb 2019 16:57:52 GMT
# gpg:                using RSA key 64DF38E8AF7E215F
# 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-tcg-20190211:
  cputlb: update TLB entry/index after tlb_fill
  exec-all: document that tlb_fill can trigger a TLB resize
  tcg/i386: fix unsigned vector saturating arithmetic
  tcg: Diagnose referenced labels that have not been emitted

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