coreboot: Add generic early SMBus API

Early SMBUS code with similar functionality is duplicated for all
southbridges. Add a generic SMBus API (function declarations) designed to
unify the early SMBus structure.

This patch only adds the API. It does not implement any hardware-specific
bits.

Change-Id: I0861b7a3f098115182ae6de9f016dd671c500bad
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: http://review.coreboot.org/143
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
1 file changed