nios2 target support

# gpg: Signature made Tue 24 Jan 2017 21:11:47 GMT
# gpg:                using RSA key 0xAD1270CC4DD0279B
# gpg: Good signature from "Richard Henderson <rth7680@gmail.com>"
# gpg:                 aka "Richard Henderson <rth@redhat.com>"
# gpg:                 aka "Richard Henderson <rth@twiddle.net>"
# Primary key fingerprint: 9CB1 8DDA F8E8 49AD 2AFC  16A4 AD12 70CC 4DD0 279B

* remotes/rth/tags/pull-nios-20170124:
  nios2: Add support for Nios-II R1
  nios2: Add Altera 10M50 GHRD emulation
  nios2: Add periodic timer emulation
  nios2: Add IIC interrupt controller emulation
  nios2: Add usermode binaries emulation
  nios2: Add disas entries
  nios2: Add architecture emulation support
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>