Merge remote-tracking branch 'remotes/alistair/tags/pull-riscv-to-apply-20200603...

Merge remote-tracking branch 'remotes/alistair/tags/pull-riscv-to-apply-20200603' into staging

This is a collection of RISC-V patches for 5.1.

This incldues removing deprecated features and part of the OpenTitan
support series.

# gpg: Signature made Wed 03 Jun 2020 17:12:43 BST
# gpg:                using RSA key F6C4AC46D4934868D3B8CE8F21E10D29DF977054
# gpg: Good signature from "Alistair Francis <alistair@alistair23.me>" [full]
# Primary key fingerprint: F6C4 AC46 D493 4868 D3B8  CE8F 21E1 0D29 DF97 7054

* remotes/alistair/tags/pull-riscv-to-apply-20200603:
  riscv: Initial commit of OpenTitan machine
  target/riscv: Add the lowRISC Ibex CPU
  target/riscv: Don't set PMP feature in the cpu init
  target/riscv: Disable the MMU correctly
  target/riscv: Don't overwrite the reset vector
  riscv/boot: Add a missing header include
  riscv: sifive_e: Manually define the machine
  docs: deprecated: Update the -bios documentation
  target/riscv: Drop support for ISA spec version 1.09.1
  target/riscv: Remove the deprecated CPUs
  hw/riscv: spike: Remove deprecated ISA specific machines
  hw/riscv: virt: Remove the riscv_ prefix of the machine* functions
  hw/riscv: sifive_u: Remove the riscv_ prefix of the soc* functions
  riscv: Change the default behavior if no -bios option is specified
  riscv: Suppress the error report for QEMU testing with riscv_find_firmware()

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