backout 6305939: causes panics in PIT

[danek.duv...@sun.com]

Author: dduvall
Repository: /hg/onnv/onnv-gate
Revision: f8c09e213366c9053797a5a6e1525bf659130b1a
Log message:
backout 6305939: causes panics in PIT

Files:
        update: usr/src/uts/common/io/sysmsg.c