perf probe: Adjust map->reloc offset when finding kernel symbol from map

Adjust map->reloc offset for the unmapped address when finding
alternative symbol address from map, because KASLR can relocate the
kernel symbol address.

The same adjustment has been done when finding appropriate kernel symbol
address from map which was introduced by commit f90acac7 ("perf
probe: Find given address from offline dwarf")
Reported-by: NArnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu@linaro.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20160806192948.e366f3fbc4b194de600f8326@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/probe-event.c

@@ -385,7 +385,7 @@ static int find_alternative_probe_point(struct debuginfo *dinfo,
 		if (uprobes)
 			address = sym->start;
 		else
-			address = map->unmap_ip(map, sym->start);
+			address = map->unmap_ip(map, sym->start) - map->reloc;
 		break;
 	}
 	if (!address) {