Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

* pc-bios/optionrom/Makefile fixes
* warning fixes for __atomic_load and -1 << x in clang
* missed interrupt fix from Gonglei
* checkpatch fix from Radim and myself

# gpg: Signature made Wed 10 Aug 2016 14:54:31 BST
# gpg:                using RSA key 0xBFFBD25F78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>"
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>"
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* remotes/bonzini/tags/for-upstream:
  checkpatch: default to success if only warnings
  checkpatch: bump most warnings to errors
  CODING_STYLE, checkpatch: update line length rules
  checkpatch: check for CVS keywords on all sources
  checkpatch: tweak the files in which TABs are checked
  timer: set vm_clock disabled default
  checkpatch: ignore automatically imported Linux headers
  clang: Fix warning reg. expansion to 'defined'
  Disable warn about left shifts of negative values
  atomic: strip "const" from variables declared with typeof
  optionrom: fix compilation with mingw docker target
  optionrom: add -fno-stack-protector
  build-sys: fix building with make CFLAGS=.. argument
  linuxboot_dma: avoid guest ABI breakage on gcc vs. clang compilation

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