Modify Get Device ID to use Context::bus

Now that a bus pointer is available via the Context for every IPMI
command handler, make use of it for Get Device ID.

Tested-by: run Get Device ID and verify results:
           ipmitool raw 6 1
             23 00 00 00 02 bf 57 01 00 7b 00 00 00 00 00

Change-Id: I2ae5f59623767c7ae059340758a8d042acfb00e9
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>
1 file changed