tests/avocado: Add tests booting YAMON ROM on MIPS Malta machines

tests/avocado: Add tests booting YAMON ROM on MIPS Malta machines

Add quick tests booting YAMON:

  $ avocado --show=app,console run -t machine:malta tests/avocado/machine_mips_malta.py
   (1/2) tests/avocado/machine_mips_malta.py:MaltaMachine.test_mipsel_malta_yamon:
  console: YAMON ROM Monitor, Revision 02.22.
  console: Copyright (c) 1999-2007 MIPS Technologies, Inc. - All Rights Reserved.
  console: For a list of available commands, type 'help'.
  console: Compilation time =              May 24 2013  12:16:34 (pburton)
  console: Board type/revision =           0x02 (Malta) / 0x00
  console: Core board type/revision =      0x01 (CoreLV) / 0x00
  console: System controller/revision =    Galileo / GT_64120A-B-0
  console: FPGA revision =                 0x0000
  console: MAC address =                   ff.ff.ff.ff.ff.ff
  console: Board S/N =                     0123456789
  console: PCI bus frequency =             33.33 MHz
  console: Processor Company ID/options =  0x01 (MIPS Technologies, Inc.) / 0x00
  console: Processor ID/revision =         0x93 (MIPS 24Kf) / 0x00
  console: Endianness =                    Little
  console: CPU/Bus frequency =             333 MHz / 419 MHz
  console: Coherency =                     None
  console: Flash memory size =             4 MByte
  console: SDRAM size =                    128 MByte
  console: First free SDRAM address =      0x800c32f0
  console: WARNING: Environment variable flash area is invalid!
  console: HINT   : Perform "erase -e"
  console: YAMON>
  PASS (1.88 s)
   (2/2) tests/avocado/machine_mips_malta.py:MaltaMachine.test_mips64el_malta_yamon:
  ...
  console: System controller/revision =    Galileo / GT_64120A-B-0
  console: Processor Company ID/options =  0x01 (MIPS Technologies, Inc.) / 0x00
  console: Processor ID/revision =         0x82 (MIPS 20Kc) / 0xa0
  ...
  console: YAMON>
  PASS (1.89 s)
  RESULTS    : PASS 2 | ERROR 0 | FAIL 0 | SKIP 0 | WARN 0 | INTERRUPT 0 | CANCEL 0
  JOB TIME   : 4.57 s

YAMON does some endian-swapped acceses on the ISD<->PCI CFG/DATA
registers. These tests are useful to debug cross-endianness issues,
in particular on big-endian host.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230104133935.4639-7-philmd@linaro.org>