Add missing code back in cartesian_config.py and utils_misc.py

Code about prepare_case and _min, _max missing during merge.
Add them back.

This patch only udpate code to print_dicts_default, may need some update
in print_dicts_repr.

Signed-off-by: Feng Yang <fyang@redhat.com>
utils_misc: Update vendor name used in cpu_types

get_cpu_vendor will return intel, amd, ibm or unknown

Signed-off-by: Feng Yang <fyang@redhat.com>
Acked-by: Suqin Huang <shuang@redhat.com>
virttest.utils_misc: small bugs fix

Signed-off-by: Yiqiao Pu <ypu@redhat.com>