Merge remote-tracking branch 'remotes/alistair/tags/pull-riscv-to-apply-20210304...

Merge remote-tracking branch 'remotes/alistair/tags/pull-riscv-to-apply-20210304' into staging

RISC-V PR for 6.0

This PR is a collection of RISC-V patches:
 - Improvements to SiFive U OTP
 - Upgrade OpenSBI to v0.9
 - Support the QMP dump-guest-memory
 - Add support for the SiFive SPI controller (sifive_u)
 - Initial RISC-V system documentation
 - A fix for the Goldfish RTC
 - MAINTAINERS updates
 - Support for high PCIe memory in the virt machine

# gpg: Signature made Thu 04 Mar 2021 14:44:31 GMT
# 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-20210304:
  hw/riscv: virt: Map high mmio for PCIe
  hw/riscv: virt: Limit RAM size in a 32-bit system
  hw/riscv: virt: Drop the 'link_up' parameter of gpex_pcie_init()
  hw/riscv: Drop 'struct MemmapEntry'
  MAINTAINERS: Add a SiFive machine section
  goldfish_rtc: re-arm the alarm after migration
  docs/system: riscv: Add documentation for sifive_u machine
  docs/system: Add RISC-V documentation
  docs/system: Sort targets in alphabetical order
  hw/riscv: sifive_u: Change SIFIVE_U_GEM_IRQ to decimal value
  hw/riscv: sifive_u: Add QSPI2 controller and connect an SD card
  hw/riscv: sifive_u: Add QSPI0 controller and connect a flash
  hw/ssi: Add SiFive SPI controller support
  hw/block: m25p80: Add various ISSI flash information
  hw/block: m25p80: Add ISSI SPI flash support
  target-riscv: support QMP dump-guest-memory
  roms/opensbi: Upgrade from v0.8 to v0.9
  hw/misc: sifive_u_otp: Use error_report() when block operation fails
  target/riscv: Declare csr_ops[] with a known size

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