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

Commit 7eec00a7 ("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: 7eec00a7 ("perf symbols: Consolidate symbol fixup issue")
Reported-by: NSandipan Das <sandipan@linux.ibm.com>
Signed-off-by: NRavi Bangoria <ravi.bangoria@linux.ibm.com>
Reviewed-by: NLeo Yan <leo.yan@linaro.org>
Reviewed-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: NSandipan Das <sandipan@linux.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lore.kernel.org/lkml/20200509112113.174745-1-ravi.bangoria@linux.ibm.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/arch/powerpc/util/Build

@@ -2,6 +2,7 @@ perf-y += header.o
 perf-y += kvm-stat.o
 perf-y += perf_regs.o
 perf-y += mem-events.o
+perf-y += sym-handling.o
 
 perf-$(CONFIG_DWARF) += dwarf-regs.o
 perf-$(CONFIG_DWARF) += skip-callchain-idx.o