perf symbols: Remove needless checks for map->groups->machine

Its sufficient to check if map->groups is NULL before using it to get
->machine value.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-utiepyiv8b1tf8f79ok9d6j8@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/symbol.c

@@ -1617,7 +1617,7 @@ int dso__load(struct dso *dso, struct map *map)
 		goto out;
 	}
 
-	if (map->groups && map->groups->machine)
+	if (map->groups)
 		machine = map->groups->machine;
 	else
 		machine = NULL;