gen_path_callouts: Create objects for segments

Create FSI, I2C, and SPI callout objects for the bus segments directly
off of the BMC.

A future commit will extend the FSI callouts to other segments further
away.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I3c34034162369bad6722bdebacd651bf37518c74
1 file changed