Frames created by the Xcpustop, Xrendezvous, Xipi_intr_bitmap_handler and Xlazypmap differ from the frame for Xtimerint. The Xtimerint puts pointer to the frame between return address and frame body, while rest of the functions listed above do not. Correct offset calculation to allow the ddb backtrace to step over such frames.
Frames created by the Xcpustop, Xrendezvous, Xipi_intr_bitmap_handler
and Xlazypmap differ from the frame for Xtimerint. The Xtimerint puts
pointer to the frame between return address and frame body, while rest
of the functions listed above do not. Correct offset calculation to
allow the ddb backtrace to step over such frames.

Noted and reviewed by:	tegge
Tested by:	pho
MFC after:	1 week

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase