PowerPC: Add systemtap static probe points in setjmp/longjmp

PowerPC: Add systemtap static probe points in setjmp/longjmp

This patch add static probes for setjmp/longjmp in the way gdb expects,fixing
the gdb.base/longjmp.exp gdb testcases.

It changes the symbol_name and use macros to to avoid change the probe names
and ending up adding more logic on GDB (since with the expected name
GDB work seamlessly).