arm-cci: remove unused variable

hw_counter is unused in the PMU IRQ handler, so remove it.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

drivers/bus/arm-cci.c

@@ -1077,13 +1077,10 @@ static irqreturn_t pmu_handle_irq(int irq_num, void *dev)
 	 */
 	for (idx = 0; idx <= CCI_PMU_CNTR_LAST(cci_pmu); idx++) {
 		struct perf_event *event = events->events[idx];
-		struct hw_perf_event *hw_counter;
 
 		if (!event)
 			continue;
 
-		hw_counter = &event->hw;
-
 		/* Did this counter overflow? */
 		if (!(pmu_read_register(cci_pmu, idx, CCI_PMU_OVRFLW) &
 		      CCI_PMU_OVRFLW_FLAG))