ppc64le: Store correct function entry address in symbol_table

ppc64le: Store correct function entry address in symbol_table

PPC64 ELF ABI v2 has a Global Entry Point and a Local Entry Point for
the functions. Debuginfo of ELF contains GEP which is same as entrypc
while symbol table contains GEP and offset, from which we can calculate
LEP. LEP is used to call function within single CU, when TOC pointer
update is not required. Placing a probe on LEP catches call from both
the GEP and the LEP but, by default, systemtap probes on GEP.

For ppc64le, Systemtap stores LEP in symbol table and prioritize symbol
table over debuginfo. But, storing LEP in symbol table has couple of
regression effect. As LEP is only required at a time of adding a probe,
don't store it in symbol table.

No need to prioritize symbol table as well because debuginfo and symbol
table both will contain Global Entry Point.

Revert commit b4c6a4b1cd00 ("Prioritize symbol table lookup for ppc64le")
partially.

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>