tests/acceptance: Test ast2600 machine

tests/acceptance: Test ast2600 machine

This tests a Debian multi-soc arm32 Linux kernel on the AST2600 based
Tacoma BMC machine.

There is no root file system so the test terminates when boot reaches
the stage where it attempts and fails to mount something.

Cc: Cleber Rosa <crosa@redhat.com>
Cc: Wainer dos Santos Moschetta <wainersm@redhat.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Tested-by: Cédric Le Goater <clg@kaod.org>
[ clg : - removed comment
        - removed ending self.vm.shutdown() ]
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20210304123951.163411-3-joel@jms.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210407171637.777743-13-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>