Refactored and added test case for BMC code update

- Split code update tests into files for BMC and Host
- Added a test case for BMC code update

Resolves openbmc/openbmc-test-automation#872

Change-Id: I4247fc2da512e01aea9790141dd5884e534982a8
Signed-off-by: Charles Paul Hofer <Charles.Hofer@ibm.com>
7 files changed