The hwclock.sh script assumes the hardware clock is kept in localtime. A variable similar to the UTC variable found in /etc/default/rcS should be used to declare whether the HW clock is in local or UTC. Based on the value of this variable, call hwclock with '--utc' or '--localtime'. BTW, if the current UTC variable in /etc/default/rcS indicates the HW clock format then the comment should be changed (i.e.: it mentions the system time (linux clock) which is different from the HW clock (bios/cmos)).
merged to poky/master: http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=7f6edde6af6451b811c1c45139f6eede525798ae