MFC r303113: Cross-link some SMBus controller drivers man pages.
MFC r293678: Update ismt(4) man page to reflect inclusion in upcoming 10.3 release.
MFC r266474: Add ismt(4) driver. ismt(4) supports the SMBus Message Transport controller found on Intel C2000 series (Avoton) and S1200 series (Briarwood) Atom SoCs.Relnotes: Yes