tests/avocado: ppc: Add smoke tests for MPC7400 and MPC7450 families

tests/avocado: ppc: Add smoke tests for MPC7400 and MPC7450 families

These tests ensure that our emulation for these cpus is not completely
broken and we can at least run OpenBIOS on them.

$ make check-avocado AVOCADO_TESTS=../tests/avocado/ppc_74xx.py

Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20220117144757.782441-1-farosas@linux.ibm.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>