Merge remote-tracking branch 'remotes/yongbok/tags/mips-20170728' into staging

MIPS patches 2017-07-28

Changes:
* Improve ths MIPS board kernel load error reporting
* Revert unnecessary warning messages

# gpg: Signature made Fri 28 Jul 2017 13:47:52 BST
# gpg:                using RSA key 0x2238EB86D5F797C2
# gpg: Good signature from "Yongbok Kim <yongbok.kim@imgtec.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 8600 4CF5 3415 A5D9 4CFA  2B5C 2238 EB86 D5F7 97C2

* remotes/yongbok/tags/mips-20170728:
  Revert "elf-loader: warn about invalid endianness"
  hw/mips: load_elf_strerror to report kernel loading failure

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