Fixed pep8/flake8 python style code for lsvmbus tool.

The TAB indentation was on purpose ignored (pep8 rule W191) to make
sure the code is complying with the Linux code guideline.
The following command doe not show any warnings now:
pep8 --ignore=W191 lsvmbus
flake8 --ignore=W191 lsvmbus
Signed-off-by: Adrian Vladu <avladu@cloudbasesolutions.com>

Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Alessandro Pilotti <apilotti@cloudbasesolutions.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>