hw/riscv: add CBQRI controllers to virt machine

Add CBQRI controllers to the RISC-V virt machine. The device properties
can be fully configured from the command line:

  $ qemu-system-riscv64 -M virt ... \
      -device riscv.cbqri.capacity,mmio_base=0x04828000[,...]
      -device riscv.cbqri.bandwidth,mmio_base=0x04829000[,...]

The mmio_base option is mandatory, the others are optional.

Many -device arguments as wanted can be provided as long as their
mmio regions don't conflict.

To see all possible options:

  $ qemu-system-riscv64 -device riscv.cbqri.capacity,help
  riscv.cbqri.capacity options:
    alloc_op_config_limit=<bool> -  (default: true)
    alloc_op_flush_rcid=<bool> -  (default: true)
    alloc_op_read_limit=<bool> -  (default: true)
    at_code=<bool>         -  (default: true)
    at_data=<bool>         -  (default: true)
    max_mcids=<uint16>     -  (default: 256)
    max_rcids=<uint16>     -  (default: 64)
    mmio_base=<uint64>     -  (default: 0)
    mon_evt_id_none=<bool> -  (default: true)
    mon_evt_id_occupancy=<bool> -  (default: true)
    mon_op_config_event=<bool> -  (default: true)
    mon_op_read_counter=<bool> -  (default: true)
    ncblks=<uint16>        -  (default: 16)
    target=<str>

  $ qemu-system-riscv64 -device riscv.cbqri.bandwidth,help
  riscv.cbqri.bandwidth options:
    alloc_op_config_limit=<bool> -  (default: true)
    alloc_op_read_limit=<bool> -  (default: true)
    at_code=<bool>         -  (default: true)
    at_data=<bool>         -  (default: true)
    max_mcids=<uint16>     -  (default: 256)
    max_rcids=<uint16>     -  (default: 64)
    mmio_base=<uint64>     -  (default: 0)
    mon_evt_id_none=<bool> -  (default: true)
    mon_evt_id_rdonly_count=<bool> -  (default: true)
    mon_evt_id_rdwr_count=<bool> -  (default: true)
    mon_evt_id_wronly_count=<bool> -  (default: true)
    mon_op_config_event=<bool> -  (default: true)
    mon_op_read_counter=<bool> -  (default: true)
    nbwblks=<uint16>       -  (default: 1024)
    target=<str>

Boolean options correspond to hardware capabilities that can be disabled

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Signed-off-by: Drew Fustini <dfustini@baylibre.com>