Changes at dof_helper_t

[Veniamin Gvozdikov]

Hi,

After upgrade to 11R i see dof_helper_t has changed.
https://svnweb.freebsd.org/base/head/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h?r1=279667&r2=281257

Would you like add to src/UPDATING for that.