arc: fix use of uninitialized arc_pmu

commit 7002f775 upstream.

static arc_pmu in the arch/arc/kernel/perf_event.c is not initialized as
it's shadowed by a local variable of the same name in the
arc_pmu_device_probe.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Fixes: 03c94fcf "ARC: perf: make @arc_pmu static global"
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/arc/kernel/perf_event.c

@@ -266,7 +266,6 @@ static int arc_pmu_add(struct perf_event *event, int flags)
 
 static int arc_pmu_device_probe(struct platform_device *pdev)
 {
-	struct arc_pmu *arc_pmu;
 	struct arc_reg_pct_build pct_bcr;
 	struct arc_reg_cc_build cc_bcr;
 	int i, j, ret;