perf powerpc: Don't ignore sym-handling.c file

perf powerpc: Don't ignore sym-handling.c file

Commit 7eec00a74720 ("perf symbols: Consolidate symbol fixup issue")
removed powerpc specific sym-handling.c file from Build. This wasn't
caught by build CI because all functions in this file are declared
as __weak in common code. Fix it.

Fixes: 7eec00a74720 ("perf symbols: Consolidate symbol fixup issue")
Reported-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Reviewed-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Sandipan Das <sandipan@linux.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lore.kernel.org/lkml/20200509112113.174745-1-ravi.bangoria@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>