meta-ibm: Add mihawk ipmi configs

1. Add dcmi config
2. Add channel config : mihawk has 2 ethernet interfaces

Tested: 1. Verify ipmitool dcmi commands work ok on mihawk
        2. Ran command : ipmitool lan print

Signed-off-by: Ben Pai <Ben_Pai@wistron.com>
Change-Id: Ia415b01204bb472a87d10b7b2da2502b78f4b374
3 files changed