Merge remote-tracking branch 'remotes/alistair/tags/pull-riscv-to-apply-20200619...

Merge remote-tracking branch 'remotes/alistair/tags/pull-riscv-to-apply-20200619-3' into staging

This is a range of patches for RISC-V.

Some key points are:
 - Generalise the CPU init functions
 - Support the SiFive revB machine
 - Improvements to the Hypervisor implementation and error checking
 - Connect some OpenTitan devices
 - Changes to the sifive_u machine to support U-boot

v2:
 - Fix missing realise assert

# gpg: Signature made Fri 19 Jun 2020 17:34:34 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-20200619-3: (32 commits)
  hw/riscv: sifive_u: Add a dummy DDR memory controller device
  hw/riscv: sifive_u: Sort the SoC memmap table entries
  hw/riscv: sifive_u: Support different boot source per MSEL pin state
  hw/riscv: sifive: Change SiFive E/U CPU reset vector to 0x1004
  target/riscv: Rename IBEX CPU init routine
  hw/riscv: sifive_u: Add a new property msel for MSEL pin state
  hw/riscv: sifive_u: Rename serial property get/set functions to a generic name
  hw/riscv: sifive_u: Add reset functionality
  hw/riscv: sifive_gpio: Do not blindly trigger output IRQs
  hw/riscv: sifive_u: Hook a GPIO controller
  hw/riscv: sifive_gpio: Add a new 'ngpio' property
  hw/riscv: sifive_gpio: Clean up the codes
  hw/riscv: sifive_u: Generate device tree node for OTP
  hw/riscv: sifive_u: Simplify the GEM IRQ connect code a little bit
  hw/riscv: opentitan: Remove the riscv_ prefix of the machine* and soc* functions
  hw/riscv: sifive_e: Remove the riscv_ prefix of the machine* and soc* functions
  target/riscv: Use a smaller guess size for no-MMU PMP
  riscv/opentitan: Connect the UART device
  riscv/opentitan: Connect the PLIC device
  hw/intc: Initial commit of lowRISC Ibex PLIC
  ...

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