perf expr: Fix copy/paste mistake

Copy/paste leftover from recent refactor.

Fixes: 26226a97 ("perf expr: Move expr lexer to flex")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200315155609.603948-1-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/expr.l

@@ -79,10 +79,10 @@ symbol		{spec}*{sym}*{spec}*{sym}*
 	{
 		int start_token;
 
-		start_token = parse_events_get_extra(yyscanner);
+		start_token = expr_get_extra(yyscanner);
 
 		if (start_token) {
-			parse_events_set_extra(NULL, yyscanner);
+			expr_set_extra(NULL, yyscanner);
 			return start_token;
 		}
 	}