tests/boot_linux_console: Add initrd test for the CubieBoard

tests/boot_linux_console: Add initrd test for the CubieBoard

This test boots a Linux kernel on a CubieBoard and verify
the serial output is working.

The kernel image and DeviceTree blob are built by the Armbian
project (based on Debian):
https://docs.armbian.com/Developer-Guide_Build-Preparation/

The cpio image used comes from the linux-build-test project:
https://github.com/groeck/linux-build-test

If ARM is a target being built, "make check-acceptance" will
automatically include this test by the use of the "arch:arm" tags.

Alternatively, this test can be run using:

  $ avocado --show=console run -t machine:cubieboard tests/acceptance/boot_linux_console.py
  console: Uncompressing Linux... done, booting the kernel.
  console: Booting Linux on physical CPU 0x0
  console: Linux version 4.20.7-sunxi (root@armbian.com) (gcc version 7.2.1 20171011 (Linaro GCC 7.2-2017.11)) #5.75 SMP Fri Feb 8 09:02:10 CET 2019
  console: CPU: ARMv7 Processor [410fc080] revision 0 (ARMv7), cr=50c5387d
  console: CPU: PIPT / VIPT nonaliasing data cache, VIPT nonaliasing instruction cache
  console: OF: fdt: Machine model: Cubietech Cubieboard
  [...]
  console: Boot successful.
  console: cat /proc/cpuinfo
  console: / # cat /proc/cpuinfo
  console: processor      : 0
  console: model name     : ARMv7 Processor rev 0 (v7l)
  console: BogoMIPS       : 832.51
  [...]
  console: Hardware       : Allwinner sun4i/sun5i Families
  console: Revision       : 0000
  console: Serial         : 0000000000000000
  console: cat /proc/iomem
  console: / # cat /proc/iomem
  console: 01c00000-01c0002f : system-control@1c00000
  console: 01c02000-01c02fff : dma-controller@1c02000
  console: 01c05000-01c05fff : spi@1c05000
  console: 01c0b080-01c0b093 : mdio@1c0b080
  console: 01c0c000-01c0cfff : lcd-controller@1c0c000
  console: 01c0d000-01c0dfff : lcd-controller@1c0d000
  console: 01c0f000-01c0ffff : mmc@1c0f000
  [...]
  PASS (54.35 s)

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Tested-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-id: 20191230110953.25496-2-f4bug@amsat.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>