This change fixes a couple of issues with OPAL IPMI driver and
implements a mechanism to detect timeouts and discard old messages left
in receive queue, to avoid old messages from being confused with the
reply of new ones.
- Implemented a mechanism to discard old messages left in receive queue after timeouts.
- Added proper handling for requests with timeout == 0.
- Fixed wrong error logic in opal_ipmi_loop.
- Fixed issue when getting ipmi-interface-id from device tree.
- Added some debugging printf's.