Use the linker to perform relocations in the SUNW_dof section rather than
doing them in drti during startup. This fixes a number of problems with
using USDT probes in stripped executables and shared libraries, and with
USDT probes in static functions.

Reviewed by: rpaulo
MFC after: 1 month
Sponsored by: EMC / Isilon Storage Division
Phabric: D751