SMBus is a subset of the I2C Protocol. From the kernel config help dialog:
I2C support (I2C)
I2C (pronounce: I-square-C) is a slow serial bus protocol used in
many micro controller applications and developed by Philips. SMBus,
or System Management Bus is a subset of the I2C protocol. More
information is contained in the directory <file:Documentation/i2c/>,
especially in the file called "summary" there.
There are a number of sub-selections within the kernel configuration, having to do with various SMBus items. Using your kernel configurator, have a look under:
Device Drivers --> I2C Support --> I2C Hardware Bus Support ...
There you can see the various SMBus controller drivers. De-selecting all those would be a first step.
To disable/remove SMBus support entirely (along with any associated/related I2C support!), you could disable (un-check) "I2C Support" under "Device Drivers" to get rid of the whole thing.
Hope this helps!